Preconception sleep duration, non-daytime work schedules, and incidence of spontaneous abortion: a prospective cohort study.

STUDY QUESTION: To what extent do self-reported sleep duration and non-daytime work schedules in either partner affect the rate of spontaneous abortion (SAB)? SUMMARY ANSWER: Incidence of SAB had little association with female sleep duration and a modest positive association with male short sleep duration, female work at night, and discrepant work schedules among partners. WHAT IS KNOWN ALREADY: Several studies have reported an association between short sleep duration in either partner and reproductive health outcomes, including fecundability. Moreover, certain types of female occupational exposures during pregnancy have been associated with an increased risk of SAB. No studies have evaluated SAB risk in relation to male sleep and work schedules, or joint exposures within a couple. STUDY DESIGN, SIZE, DURATION: This prospective cohort study included 9357 female participants and 2602 of their male partners residing in North America (June 2013 to April 2023). PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants enrolled when they were attempting pregnancy and completed self-administered baseline questionnaires about their average sleep duration and work schedules. Among those who conceived, we ascertained SAB and gestational age at loss via follow-up questionnaires. We used multivariable Cox proportional hazards models with gestational weeks as the time scale to estimate hazard ratios (HRs) and 95% CIs relating SAB with sleep duration and non-daytime work schedules for female and male participants, and the couple. We used inverse probability weighting to account for potential selection bias due to the possibility of differential participation of male partners with respect to the exposures. MAIN RESULTS AND THE ROLE OF CHANCE: Compared to female participants with recommended sleep (7-8.9 h), those reporting short sleep duration (<6 h) did not have a higher rate of SAB (HR 0.88, 95% CI 0.69, 1.13). Short self-reported sleep duration among male participants was modestly associated with a higher rate of SAB (adjusted and weighted HR 1.30, 95% CI 0.96, 1.75). Female night work at night (adjusted HR 1.19, 95% CI 1.02, 1.38) and male non-daytime work (adjusted and weighted HR 1.26, 95% CI 1.00, 1.59) were associated with modestly higher rates of SAB, whereas female rotating shift work was not (adjusted HR 0.91, 0.78, 1.05) compared with daytime workers. Couples in which work schedules were discrepant had an elevated rate of SAB if the male partner worked a non-daytime shift (adjusted and weighted HR 1.46, 95% CI 1.13, 1.88) compared with couples in which both members worked during the day. The corresponding HR if only the female partner worked a non-daytime shift was 1.21 (95% CI 0.92, 1.58). LIMITATIONS, REASONS FOR CAUTION: Data on sleep duration and work schedules were based on self-report, which is vulnerable to misclassification, particularly since participants were asked to report their average sleep duration during the past month. Work exposures were heterogeneous, as many different types of employment may require night and shift work and may have different associations with SAB. WIDER IMPLICATIONS OF THE FINDINGS: Our findings are consistent with previous research indicating that some types of female employment schedules may be associated with SAB incidence. This is the first study to indicate a relationship between SAB and male employment schedules, indicating that discrepant work schedules within a couple might be relevant. STUDY FUNDING/COMPETING INTEREST(S): This work was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development grants R01HD105863 (PIs: L.A.W. and M.L.E.), R01HD086742 (PIs: L.A.W. and E.E.H.), and R21HD072326 (PI: L.A.W.). PRESTO has received in-kind donations from Swiss Precision Diagnostics and Kindara.com for primary data collection. L.A.W. is a consultant for AbbVie, Inc. and the Gates Foundation. M.L.E. is an advisor for and holds stock in Ro, Hannah, Dadi, Underdog, Vseat, & Doveras. The other authors have no competing interests to declare. TRIAL REGISTRATION NUMBER: N/A.

Self-reported periodontitis and fecundability in a population of pregnancy planners.

STUDY QUESTION: Is a history of periodontitis among women associated with reduced fecundability? SUMMARY ANSWER: A history of periodontitis, as assessed by three different self-reported measures, may be associated with reduced fecundability. WHAT IS KNOWN ALREADY: Periodontitis is a chronic inflammatory condition affecting the hard and soft tissues surrounding the teeth. Few studies have evaluated the association between periodontitis and time to pregnancy, and findings are mixed. It is hypothesized that periodontitis may adversely affect time to pregnancy. STUDY DESIGN, SIZE, DURATION: We conducted a prospective cohort study of 2764 female pregnancy planners residing in North America (March 2015-June 2020). PARTICIPANTS/MATERIALS, SETTING, METHODS: Eligible participants had been attempting pregnancy for six or fewer menstrual cycles at enrollment and were not using fertility treatment. Women answered questions about their oral health. Pregnancy was ascertained via bi-monthly follow-up questionnaires. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs) for three different measures indicative of a history of periodontitis: ever diagnosed with periodontitis (N = 265), ever received treatment for periodontitis (N = 299), and ever had an adult tooth become loose on its own (N = 83). We adjusted for potential confounders and precision variables. Women at risk of misclassification of periodontitis diagnosis due to pregnancy-related gingivitis were reclassified in a sensitivity analysis. MAIN RESULTS AND THE ROLE OF CHANCE: All three indices of periodontitis may be associated with reduced fecundability. FRs were 0.89 (95% CI 0.75-1.06) comparing women with and without a previous periodontitis diagnosis, 0.79 (95% CI 0.67-0.94) comparing women with and without previous periodontitis treatment, and 0.71 (95% CI 0.44-1.16) comparing women with and without a tooth that became loose. After reclassification of pregnancy-related gingivitis in the sensitivity analysis, the FR for periodontitis diagnosis was 0.83 (95% CI 0.68-1.00). Weaker FRs were observed among parous women as compared with nulliparous women for periodontitis diagnosis and tooth becoming loose, but not for periodontitis treatment. LIMITATIONS, REASONS FOR CAUTION: Though we used validated self-report measures of periodontitis, clinical confirmation is the gold standard. These questions may be functioning as markers of different levels of periodontitis severity, but we were unable to measure disease severity in this population. Finally, we cannot eliminate the possibility of unmeasured confounding. WIDER IMPLICATIONS OF THE FINDINGS: This is the first preconception prospective cohort study to evaluate the association between self-reported periodontitis and fecundability. Our results indicate that periodontitis may be associated with lower fecundability. STUDY FUNDING/COMPETING INTEREST(S): This work was partially funded by R01HD086742/Eunice Kennedy Shriver National Institute of Child Health and Human Development and R21HD072326/Eunice Kennedy Shriver National Institute of Child Health and Human Development. PRESTO has received in-kind donations from Swiss Precision Diagnostics, Sandstone Diagnostics, FertilityFriend.com, and Kindara.com for primary data collection. L.A.W. is a fibroid consultant for AbbVie, Inc. J.C.B., S.W., J.Y., K.J.R., E.E.H., and B.H. have no conflicts of interest to disclose. TRIAL REGISTRATION NUMBER: N/A.

Male cellular telephone exposure, fecundability, and semen quality: results from two preconception cohort studies.

STUDY QUESTION: To what extent is exposure to cellular telephones associated with male fertility? SUMMARY ANSWER: Overall, we found little association between carrying a cell phone in the front pants pocket and male fertility, although among leaner men (BMI <25 kg/m2), carrying a cell phone in the front pants pocket was associated with lower fecundability. WHAT IS KNOWN ALREADY: Some studies have indicated that cell phone use is associated with poor semen quality, but the results are conflicting. STUDY DESIGN, SIZE, DURATION: Two prospective preconception cohort studies were conducted with men in Denmark (n = 751) and in North America (n = 2349), enrolled and followed via the internet from 2012 to 2020. PARTICIPANTS/MATERIALS, SETTING, METHODS: On the baseline questionnaire, males reported their hours/day of carrying a cell phone in different body locations. We ascertained time to pregnancy via bi-monthly follow-up questionnaires completed by the female partner for up to 12 months or until reported conception. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs) for the association between male cell phone habits and fecundability, focusing on front pants pocket exposure, within each cohort separately and pooling across the cohorts using a fixed-effect meta-analysis. In a subset of participants, we examined selected semen parameters (semen volume, sperm concentration and sperm motility) using a home-based semen testing kit. MAIN RESULTS AND THE ROLE OF CHANCE: There was little overall association between carrying a cell phone in a front pants pocket and fecundability: the FR for any front pants pocket exposure versus none was 0.94 (95% CI: 0.0.83-1.05). We observed an inverse association between any front pants pocket exposure and fecundability among men whose BMI was <25 kg/m2 (FR = 0.72, 95% CI: 0.59-0.88) but little association among men whose BMI was ≥25 kg/m2 (FR = 1.05, 95% CI: 0.90-1.22). There were few consistent associations between cell phone exposure and semen volume, sperm concentration, or sperm motility. LIMITATIONS, REASONS FOR CAUTION: Exposure to radiofrequency radiation from cell phones is subject to considerable non-differential misclassification, which would tend to attenuate the estimates for dichotomous comparisons and extreme exposure categories (e.g. exposure 8 vs. 0 h/day). Residual confounding by occupation or other unknown or poorly measured factors may also have affected the results. WIDER IMPLICATIONS OF THE FINDINGS: Overall, there was little association between carrying one's phone in the front pants pocket and fecundability. There was a moderate inverse association between front pants pocket cell phone exposure and fecundability among men with BMI <25 kg/m2, but not among men with BMI ≥25 kg/m2. Although several previous studies have indicated associations between cell phone exposure and lower sperm motility, we found few consistent associations with any semen quality parameters. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by the National Institutes of Health, grant number R03HD090315. In the last 3 years, PRESTO has received in-kind donations from Sandstone Diagnostics (for semen kits), Swiss Precision Diagnostics (home pregnancy tests), Kindara.com (fertility app), and FertilityFriend.com (fertility app). Dr. L.A.W. is a fibroid consultant for AbbVie, Inc. Dr. H.T.S. reports that the Department of Clinical Epidemiology is involved in studies with funding from various companies as research grants to and administered by Aarhus University. None of these studies are related to the current study. Dr. M.L.E. is an advisor to Sandstone Diagnostics, Ro, Dadi, Hannah, and Underdog. Dr. G.J.S. holds ownership in Sandstone Diagnostics Inc., developers of the Trak Male Fertility Testing System. In addition, Dr. G.J.S. has a patent pending related to Trak Male Fertility Testing System issued. TRIAL REGISTRATION NUMBER: N/A.

Male alcohol consumption and fecundability.

STUDY QUESTION: Does male alcohol consumption affect fecundability? SUMMARY ANSWER: In data pooled across Danish and North American preconception cohort studies, we found little evidence of an association between male alcohol consumption and reduced fecundability. WHAT IS KNOWN ALREADY: Experimental and clinical studies have shown that alcohol affects male reproductive physiology, mainly by altering male reproductive hormones and spermatogenesis. However, few epidemiologic studies have examined the association between alcohol consumption and male fertility. STUDY DESIGN, SIZE, DURATION: Data were collected from two ongoing prospective preconception cohort studies: the Danish 'SnartForaeldre' (SF) study (662 couples) and the North American 'Pregnancy Study Online' (PRESTO) (2017 couples). Participants included in the current analysis were enrolled from August 2011 through June 2019 (SF) and from June 2013 through June 2019 (PRESTO). PARTICIPANTS/MATERIALS, SETTING, METHODS: Eligible men were aged ≥18 years in SF and ≥21 years in PRESTO, in a stable relationship with a female partner and not using contraception or receiving fertility treatment. In both cohorts, alcohol consumption/serving size was self-reported as number of beers (330 mL/12 oz.), glasses of white or red wine (120 mL/4 oz. each), dessert wine (50 mL/2 oz.) and spirits (20 mL/1.5 oz.). Overall alcohol consumption was categorized as none, 1-5, 6-13 and ≥14 standard servings per week. Total menstrual cycles at risk were calculated using data from female partners' follow-up questionnaires, which were completed every 8 weeks until self-reported pregnancy or 12 menstrual cycles, whichever came first. Analyses were restricted to couples that had been trying to conceive for ≤6 cycles at study entry. Proportional probability regression models were used to compute fecundability ratios (FRs) and 95% confidence interval (CIs). We adjusted for male and female age, female partner's alcohol consumption, intercourse frequency, previous history of fathering a child, race/ethnicity, education, BMI, smoking and consumption of sugar-sweetened beverages and caffeine. MAIN RESULTS AND THE ROLE OF CHANCE: The cumulative proportion of couples who conceived during 12 cycles of follow-up were 1727 (64.5%). The median (interquartile range) of total male alcohol consumption was 4.5 (2.0-7.8) and 4.1 (1.0-8.6) standard servings per week in the SF and PRESTO cohorts, respectively. In pooled analyses, adjusted FRs for male alcohol consumption of 1-5, 6-13 and ≥14 standard servings per week compared with no alcohol consumption were 1.02 (95% CI: 0.90-1.17), 1.10 (95% CI: 0.96-1.27) and 0.98 (95% CI: 0.81-1.18), respectively. For SF, adjusted FRs of 1-5, 6-13 and ≥14 standard servings per week compared with no alcohol consumption were 0.97 (95% CI: 0.73-1.28), 0.81 (95% CI: 0.60-1.10) and 0.82 (95% CI: 0.51-1.30), respectively. For PRESTO, adjusted FRs of 1-5, 6-13 and ≥14 standard servings per week compared with no alcohol consumption were 1.02 (95% CI: 0.88-1.18), 1.20 (95% CI: 1.03-1.40) and 1.03 (95% CI: 0.84-1.26), respectively. LIMITATIONS, REASONS FOR CAUTION: Male alcohol consumption was ascertained at baseline only, and we did not distinguish between regular and binge drinking. In addition, we had insufficient numbers to study the effects of specific types of alcoholic beverages. As always, residual confounding by unmeasured factors, such as dietary factors and mental health, cannot be ruled out. Comorbidities thought to play a role in the reproductive setting (i.e. cancer, metabolic syndrome) were not considered in this study; however, the prevalence of cancer and diabetes was low in this age group. Findings for the highest categories of alcohol consumption (6-13 and ≥14 servings/week) were not consistent across the two cohorts. WIDER IMPLICATIONS OF THE FINDINGS: Despite little evidence of an association between male alcohol consumption and reduced fecundability in the pooled analysis, data from the Danish cohort might indicate a weak association between reduced fecundability and consumption of six or more servings per week. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the National Institutes of Health (R01-HD060680, R01-HD086742, R21-HD050264, R21-HD072326, R03-HD090315), the Novo Nordisk Foundation, Oticon Fonden, Politimester J.P.N. Colind og hustru Asmine Colinds mindelegat and Erna og Peter Houtveds studielegat. PRESTO receives in-kind donations from FertilityFriend.com, Kindara.com, Swiss Precision Diagnostics and Sandstone Diagnostics for the collection of data pertaining to fertility. Dr Wise serves as a consultant on uterine leiomyomata for AbbVie.com. All other authors declare no conflict of interest.

Lubricant use during intercourse and time to pregnancy: a prospective cohort study.

OBJECTIVE: To assess the extent to which lubricant use during intercourse is associated with time to pregnancy (TTP). DESIGN: Prospective cohort study. SETTING: Denmark and North America. POPULATION: A total of 6467 women aged 18-49 years who were not using contraception or fertility treatment. METHODS: We pooled data from two continuing prospective cohort studies of pregnancy planners in Denmark (2011-2017) and North America (2013-2017). Female participants completed bimonthly questionnaires for 12 months or until they reported pregnancy. After restricting the study to women without a history of infertility who had been trying to conceive for six or fewer cycles at enrollment, 6467 women were retained for analysis. Self-reported lubricant use was categorised as water-based/not pH balanced, water-based/pH balanced 'fertility friendly', silicone-based, oil-based, or a combination of these. We used proportional probability models to calculate fecundability ratios (FRs) and 95% confidence intervals (95% CIs) for the association between lubricant use and fecundability, after adjusting for cohort and sociodemographic and lifestyle factors. MAIN OUTCOME MEASURE: Fecundability. RESULTS: At baseline, 17.5% of participants reported the use of lubricants, most commonly water-based/not pH balanced (11.4%). Compared with non-use of lubricants, FRs were 1.02 (95% CI 0.93-1.11) for water-based/not pH-balanced lubricant use, 1.01 (95% CI 0.86-1.18) for water-based/pH balanced 'fertility friendly' lubricant use, 1.23 (95% CI 0.94-1.61) for oil-based lubricant use, and 1.27 (95% CI 0.93-1.73) for silicone-based lubricant use. Associations between oil-based lubricant use and fecundability were inconsistent across subgroups of study cohort, age, parity, and intercourse frequency. CONCLUSIONS: Lubricant use was not associated with reduced fecundability in the preconception cohorts of pregnancy planners studied. TWEETABLE ABSTRACT: Lubricant use during intercourse was not associated with time to pregnancy in a study of pregnancy planners.

A prospective cohort study of a woman's own gestational age and her fecundability.

STUDY QUESTION: What is the magnitude of the association between a woman's gestational age at her own birth and her fecundability (cycle-specific probability of conception)? SUMMARY ANSWER: We found a 62% decrease in fecundability among women born <34 weeks of gestation relative to women born at 37-41 weeks of gestation, whereas there were few differences in fecundability among women born at later gestational ages. WHAT IS KNOWN ALREADY: One study, using retrospectively collected data on time-to-pregnancy (TTP), and self-reported data on gestational age, found a prolonged TTP among women born <37 gestational weeks (preterm) and with a birthweight ≤1500 g. Other studies of women's gestational age at birth and subsequent fertility, based on data from national birth registries, have reported a reduced probability of giving birth among women born <32 weeks of gestation. STUDY DESIGN, SIZE, DURATION: We used data from a prospective cohort study of Danish pregnancy planners ('Snart-Gravid'), enrolled during 2007-2011 and followed until 2012. In all, 2814 women were enrolled in our study, of which 2569 had complete follow-up. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women eligible to participate were 18-40 years old at study entry, in a relationship with a male partner, and attempting to conceive. Participants completed a baseline questionnaire and up to six follow-up questionnaires until the report of pregnancy, discontinuation of pregnancy attempts, beginning of fertility treatment, loss to follow-up or end of study observation after 12 months. MAIN RESULTS AND THE ROLE OF CHANCE: Among women born <34 gestational weeks, the cumulative probability of conception was 12, 28 and 48% within 3, 6 and 12 cycles, respectively. Among women born at 37-41 weeks of gestation, cumulative probability of conception was 47, 67 and 84% within 3, 6 and 12 cycles, respectively. Relative to women born at 37-41 weeks' gestation, women born <34 weeks had decreased fecundability (fecundability ratio (FR) 0.38, 95% confidence interval (CI): 0.17-0.82). Our data did not suggest reduced fecundability among women born at 34-36 weeks of gestation or at ≥42 weeks of gestation (FR 1.03, 95% CI: 0.80-1.34, and FR 1.13, 95% CI: 0.96-1.33, respectively). LIMITATIONS, REASONS FOR CAUTION: Data on gestational age, obtained from the Danish Medical Birth Registry, were more likely to be based on date of last menstrual period than early ultrasound examination, possibly leading to an overestimation of gestational age at birth. Such overestimation, however, would not explain the decrease in fecundability observed among women born <34 gestational weeks. Another limitation is that the proportion of women born before 34 weeks of gestation was low in our study population, which reduced the precision of the estimates. WIDER IMPLICATIONS OF THE FINDINGS: By using prospective data on TTP, our study elaborates on previous reports of impaired fertility among women born preterm, suggesting that women born <34 weeks of gestation have reduced fecundability. STUDY FUNDING/COMPETING INTERESTS: The study was supported by the National Institute of Child Health and Human Development (R21-050264), the Danish Medical Research Council (271-07-0338), and the Health Research Fund of Central Denmark Region (1-01-72-84-10). The authors have no competing interests to declare.

Caffeine and caffeinated beverage consumption and risk of spontaneous abortion.

STUDY QUESTION: Is caffeine and caffeinated beverage consumption associated with the risk of spontaneous abortion (SAB)? SUMMARY ANSWER: While preconceptional caffeine consumption was not materially associated with an increased risk of SAB, consumption during early pregnancy was associated with a small increased risk of SAB, although the relation was not linear. WHAT IS KNOWN ALREADY: Caffeine has been hypothesized as a risk factor for SAB since the 1980s; however, results from previous studies have been conflicting. STUDY DESIGN, SIZE, DURATION: This prospective cohort study included 5132 Danish women planning pregnancy and enrolled from 2007 to 2010. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were women who conceived after entry into the Snart-Gravid cohort and who were aged 18-40, in a stable relationship with a male partner, and did not use fertility treatments to conceive. Women reported their daily caffeine and caffeinated beverage consumption on questionnaires before conception and during early pregnancy. All exposure measurements were prospective with respect to outcome ascertainment. We estimated hazard ratios (HRs) of SAB for categories of caffeine consumption in milligrams (mg) per day and the corresponding 95% confidence intervals (CIs) using Cox proportional hazards regression models with gestational weeks as the time scale. MAIN RESULTS AND THE ROLE OF CHANCE: There were 732 women (14.3%) who were identified as having a SAB. In the preconceptional period, caffeine consumption was not materially associated with SAB risk (HR comparing ≥300 with <100 mg/day: 1.09; 95% CI: 0.89, 1.33). In early pregnancy, the HRs for 100-199, 200-299 and ≥300 mg/day of caffeine consumption were 1.62 (95% CI: 1.19, 2.22), 1.48 (95% CI: 1.03, 2.13) and 1.23 (95% CI: 0.61, 2.46), respectively, compared with that for <100 mg/day. LIMITATIONS, REASONS FOR CAUTION: The observed results may be affected by non-differential exposure misclassification, reverse causation and residual confounding. WIDER IMPLICATIONS OF THE FINDINGS: This is the largest study to date of prospectively measured, preconception caffeine consumption and risk of SAB. We were able to reduce the likelihood of differential left truncation bias and recall bias present in other analyses. STUDY FUNDING/COMPETING INTERESTS: Snart-Gravid was funded by the NICHD (R21-050264). Dr. Hahn's work was funded in part by the BU Reproductive, Perinatal, and Pediatric Epidemiology Training Grant NIH #T32HD052458. There are no competing interests.

Cohort study of malignancies and hospitalized infectious events in treated and untreated patients with psoriasis and a general population in the United States.

BACKGROUND: Psoriasis is associated with risk of malignancy. Some psoriasis treatments may increase the risk of hospitalized infectious events (HIEs). OBJECTIVES: To evaluate rates of malignancies and HIEs in patients with psoriasis. METHODS: This retrospective cohort study utilized data from MarketScan(®) databases. Cohorts included adult general population (GP), patients with psoriasis, and patients with psoriasis treated with nonbiologics, adalimumab, etanercept, infliximab or phototherapy. Outcomes included incidence rates (IRs) per 10 000 person-years observation (PYO) for all malignancies excluding nonmelanoma skin cancer (NMSC), lymphoma, NMSC, and per 10 000 person-years of exposure (PYE) for HIEs. RESULTS: Incidence rates [95% confidence interval (CI)] for all malignancies except NMSC were 129 (127-130) and 142 (135-149) for GP (PYO = 51 071 587) and psoriasis (PYO = 119 432) cohorts, respectively; 10·9 (10·5-11·3) and 12·9 (10·9-14·8) for lymphoma; and 145 (144-147) and 180 (173-188) for NMSC. Rates for all malignancies excluding NMSC were similar among treatments but variable for lymphoma and NMSC. IRs (95% CI) for HIEs were 332 (256-408) for the nonbiologic cohort (PYE = 3528); 288 (206-370) for etanercept (PYE = 6563); 325 (196-455) for adalimumab (PYE = 2772); 521 (278-765) for infliximab (PYE = 1058); and 334 (242-427) for phototherapy (PYE = 1797). IRs for HIEs were lowest for etanercept and higher in patients on baseline systemic corticosteroids across treatment cohorts. CONCLUSIONS: Malignancy rates were higher in patients with psoriasis than the GP, but these treatments did not appear to increase malignancy risk.

Incidence rates of malignancies and hospitalized infectious events in patients with psoriasis with or without treatment and a general population in the U.S.A.: 2005-09.

BACKGROUND: Rates of malignancies and hospitalized infectious events (HIEs) among psoriasis patients are higher than in the general population, but it is unclear if higher rates are associated with the underlying inflammatory state, treatments or both. OBJECTIVES: To assess the incidence of malignancies and HIEs in a healthy US population, a psoriasis population, and four treated psoriasis populations. METHODS: Using a US claims database, we identified a general population, a psoriasis cohort, and four treatment cohorts [non-biologic systemics, etanercept, other TNF blockers (adalimumab, infliximab) and phototherapy] to assess the incidence of lymphomas, nonmelanoma skin cancer (NMSC), all malignancies (excluding NMSC), and HIEs, standardized for age and sex. RESULTS: Among 40 987 patients with psoriasis, 11% were prescribed non-biologics, 15% etanercept, 6% other TNF blockers and 11% phototherapy. For all cancers, the psoriasis population rate (114/10 000 person-years) was 20% greater than the rate found in the general population (95/10 000 person-years). For NMSC, the psoriasis population rate (129/10 000 person-years) was 65% greater than the general population rate (78/10 000 person-years). The incidence rate for each treatment modality was lower than the overall psoriasis cohort, except for phototherapy. There was little difference in the rates of lymphomas. NMSC rates were higher among patients treated with phototherapy. HIE rates ranged from 165/10 000 person-years for the phototherapy group to 262/10 000 person-years for the other anti-TNF group. CONCLUSIONS: Patients with psoriasis appear to have higher rates of malignancy and HIE than the general population, with little difference in rates between the treatment methods, except for a higher rate of cancer among those receiving phototherapy.

Evaluation of cancer risk related to atopic dermatitis and use of topical calcineurin inhibitors.

Cases of lymphoma or cutaneous cancer have been observed following use of topical calcineurin inhibitors (TCIs), but it is unclear whether TCI use increases cancer risk. We used published literature to assess the extent to which atopic dermatitis (AD) or TCI use is associated with lymphoma, melanoma, basal cell carcinoma and squamous cell carcinoma. We searched the literature and summarized the results of all studies that provided data on the absolute or relative frequency of any malignancy among patients with AD or eczema or among patients using TCIs. The relative risk for all lymphoma in broad populations of AD or eczema ranged from 0·7 to 1·8. Available data on lymphoma following TCI use were inconsistent and insufficient to draw a conclusion about the causal role of TCIs. We found no evidence indicating that melanoma or nonmelanoma skin cancer is associated with TCI use. A bias analysis showed that cutaneous T-cell lymphomas initially misdiagnosed and treated as AD would lead to overestimation of the association between TCI use and lymphoma. However, there are only sparse data on specific malignancies among TCI-treated patients. The short duration of typical TCI exposure hinders conclusions about longer exposure. There is insufficient evidence in the epidemiological literature to infer whether TCIs do or do not cause malignancy.

Examining secular trends and seasonality in count data using dynamic generalized linear modelling: a new methodological approach illustrated with hospital discharge data on myocardial infarction.

Time series of incidence counts often show secular trends and seasonal patterns. We present a model for incidence counts capable of handling a possible gradual change in growth rates and seasonal patterns, serial correlation, and overdispersion. The model resembles an ordinary time series regression model for Poisson counts. It differs in allowing the regression coefficients to vary gradually over time in a random fashion. During the 1983-1999 period, 17,989 incidents of acute myocardial infarction were recorded in the Hospital Discharge Registry for the county of North Jutland, Denmark. Records were updated daily. A dynamic model with a seasonal pattern and an approximately linear trend was fitted to the data, and diagnostic plots indicated a good model fit. The analysis conducted with the dynamic model revealed peaks coinciding with above-average influenza A activity. On average the dynamic model estimated a higher peak-to-trough ratio than traditional models, and showed gradual changes in seasonal patterns. Analyses conducted with this model provide insights not available from more traditional approaches.

BMI-related errors in the measurement of obesity.

Body mass index (BMI) has various deficiencies as a measure of obesity, especially when the BMI measure is based on self-reported height and weight. BMI is an indirect measure of body fat compared with more direct approaches such as bioelectrical impedance. Moreover, BMI does not necessarily reflect the changes that occur with age. The proportion of body fat increases with age, whereas muscle mass decreases, but corresponding changes in height, weight and BMI may not reflect changes in body fat and muscle mass. Both the sensitivity and specificity of BMI have been shown to be poor. Additionally, the relation between BMI and percentage of body fat is not linear and differs for men and women. The consequences of the errors in the measurement of obesity with BMI depend on whether they are differential or nondifferential. Differential misclassification, a potentially greater problem in case-control and cross-sectional studies than in prospective cohort studies, can produce a bias toward or away from the null. Nondifferential misclassification produces a bias toward the null for a dichotomous exposure; for measures of exposure that are not dichotomous, the bias may be away from the null. In short, the use of BMI as a measure of obesity can introduce misclassification problems that may result in important bias in estimating the effects related to obesity.

Epidemiology of endometrial cancer.

For a population-based, case-control study of cancer of the endometrium in Greater Boston from 1965 through mid-1969, 440 cases were drawn from nearly all hospitals in the area; controls were drawn at random from the general population. The age-adjusted incidence rate was 18.1/100,000 woman-years, with a peak at ages 55-59 and a gradual decline thereafter. Information was provided from 212 cases and 1,198 controls by mall questionnaire. A trend of reduced risk of endometrial cancer with increased parity was noted, the relative incidence (RI) for multiparous women being 0.3 compared to a RI of unity for married nulliparous women. The association of risk with age at first birth was irregular. Early menarche (RI=1.6) and late menopause (RI=1.7) were associated with increased risk of disease. Endometrial cancer risk was also found to be directly related to socioeconomic status, relative weight, diabetes, hypertension, and arthritis. The findings supported the idea that hormone activity during, and perhaps after, reproductive life is an important cause of this disease.

Maternal age and birth rank of women with breast cancer.

Data from a large international case-control study of breast cancer suggested that women born to young mothers had a 25% lower risk of breast cancer. The association was not secondary to a tendency for these women themselves to have had children at early ages. The data provided no indication of a meaningful association between breast cancer risk and birth rank. Confounding was controlled by stratification according to a summary confounder score.

Effect of Corynebacterium parvum on the response to irradiation of a C3H fibrosarcoma.

A methylcholanthrene-induced fibrosarcoma of C3H mice has been used as 5th- to 6th-generation syngeneic transplant in an investigation of the role of Corynebacterium parvum as an adjuvant to the therapeutic effect of local irradiation of established tumors. The most effective route for administration of C. parvum in this tumor system was i.v., and the greatest effect of the C. parvum-mediated tumor graft rejection was observed for tumor growing intracutaneously or s.c. An intermediate level of effectiveness was obtained for tumor growing i.m. The combined C. parvum and local irradiation studies were performed using tumors growing in the leg muscle and measuring 8 mm in diameter at the time of local irradiation. Several routes of administration of C. parvum, dose levels of C. parvum, and time relationships between administration of C. parvum and irradiation were investigated. The outstanding finding was that very low doses of radiation were quite effective when administered to tumors growing in animals pretreated with C. parvum. This was true for radiation administered as a single or fractionated dose (10 equal doses spread over 18 days). For single-dose irradiation the effect was relatively dose independent over the range of 200 to 3000 rads. Some indication was obtained that local irradiation may impair the tumor graft rejection reaction. No evidence was obtained of an enhanced growth of tumor. Regression of tumor following irradiation was not modified by pretreatment with C. parvum. The mice that were unsuccessfully treated by radiation and C. parvum had a lower incidence of metastatic disease in the lung than did the mice treated unsuccessfully with radiation alone.

Folic acid supplementation and fecundability: a Danish prospective cohort study.

BACKGROUND/OBJECTIVES: Periconceptional folic acid (FA) supplementation reduces the risk of neural tube defects and has been associated with ovulatory function. However, only two studies have associated supplementation with multivitamins (MVs) that contained FA with increased pregnancy rates. We aimed to examine the association between FA supplementation (obtained either through single FA tablets or through MVs) and fecundability. SUBJECTS/METHODS: A prospective cohort study of 3895 Danish women who were planning a pregnancy between 2007 and 2011. We estimated fecundability ratios (FRs) and 95% confidence intervals (CIs) in relation to FA supplementation (either through single FA tablets or MV) using a proportional probabilities regression model, with adjustment for potential socio-demographic, reproductive and lifestyle confounders. In stratified analyses, we also estimated FR with 95% CI in relation to FA supplementation for women with regular and irregular cycles, respectively, and for women with short (<27 days), medium (27-29 days) and long cycles (⩾30 days), respectively. RESULTS: FA supplementation was associated with increased fecundability (FR=1.15, 95% CI=1.06-1.25), compared with non-use. The adjusted FRs for FA supplement use relative to non-use were 1.35 (95% CI=1.12-1.65) and 1.11 (95% CI=1.01-1.22) for women with irregular and regular cycles, respectively, and 1.36 (95% CI=0.95-1.95), 1.10 (95% CI=0.98-1.22) and 1.24 (95% CI=1.10-1.41) for women with short (<27 days), medium (27-29 days) and long cycles (⩾30 days), respectively. CONCLUSIONS: FA supplementation was associated with increased fecundability, and this association appeared to be stronger among women with irregular cycles and among women with either short or long cycle length.

Lung cancer in young women.

A comparison was made between cigarette smoking histories of 31 women below age 50 years who had a diagnosis of lung cancer on hospital discharge and smoking histories of 124 women below age 50 years who had been hospitalized for other conditions. Of the women with lung cancer, 28 (90%) were current or former cigarette smokers; 72 (58%) of the comparison women were smokers. The relative risk estimate for lung cancer among smokers as compared with nonsmokers is 6.7, with 90% confidence limits of 4.0 and 11. Risk of lung cancer increased with the amount that the women smoked. The smokers with lung cancer had been smoking for longer periods than the smokers with other conditions. Assuming that the association is causal, cigarette smoking was responsible for about 77% of the lung cancer of young women in this survey.

Preconception venous thromboembolism and placenta-mediated pregnancy complications.

BACKGROUND: Placenta-mediated complications are leading causes of maternal and fetal morbidity and mortality. We hypothesized that a preconception history of venous thromboembolism (VTE) is associated with increased risk of placenta-mediated pregnancy complications. METHODS: A nationwide population-based cohort study of all singleton pregnancies leading to delivery from 1997 to 2012 (n = 964 967). We obtained data on placenta-mediated pregnancy complications from the Danish Medical Birth Registry and data on VTE before pregnancy from the Danish National Patient Registry. We computed absolute risks, crude and adjusted risk differences (RDs) using a binomial regression model, and crude and adjusted risk ratios (RRs) from a modified Poisson regression model. RESULTS: Overall, 1419 women had a preconception history of VTE, while 578 112 did not. Preeclampsia occurred in 4.2% of pregnancies in the VTE group and in 2.7% of pregnancies in a comparison cohort (adjusted RD = 1.3%, 95% confidence interval (CI) 0.6-2.0%; adjusted RR = 1.5, 95% CI 1.3-1.8). Stillbirth occurred in 0.7% of pregnancies in the VTE group and in 0.4% of pregnancies in the comparison cohort (adjusted RD = 0.3%, 95% CI 0.02-0.6%; adjusted RR = 1.8, 95% CI 1.1-3.0). Placental abruption occurred in 0.8% of pregnancies in the VTE group and in 0.5% of pregnancies in the comparison cohort (adjusted RD = 0.3%, 95% CI - 0.05-0.6%; adjusted RR = 1.6, 95% CI 1.1-2.4). Small-for-gestational-age infants accounted for 10.9% of live births in the VTE group and 9.8% of live births in the comparison cohort (adjusted RD = 0.6%, 95% CI - 0.5-1.7%; adjusted RR = 1.1, 95% CI 0.9-1.3). CONCLUSION: Women with a history of VTE were at increased risk of placenta-mediated complications.

Prenatal diethylstilbestrol exposure and reproductive hormones in premenopausal women.

Diethylstilbestrol (DES), a synthetic estrogen widely prescribed to pregnant women in the mid-1900s, is a potent endocrine disruptor. Prenatal DES exposure has been associated with reproductive disorders in women, but little is known about its effects on endogenous hormones. We assessed the association between prenatal DES exposure and reproductive hormones among participants from the Harvard Study of Moods and Cycles (HSMC), a longitudinal study of premenopausal women aged 36-45 years from Massachusetts (1995-1999). Prenatal DES exposure was reported at baseline (43 DES exposed and 782 unexposed). Early follicular-phase concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol were measured at baseline and every 6 months during 36 months of follow-up. Inhibin B concentrations were measured through 18 months. We used multivariable logistic and repeated-measures linear regression to estimate odds ratios (OR) and percent differences in mean hormone values (ß), respectively, comparing DES exposed with unexposed women, adjusted for potential confounders. DES-exposed women had lower mean concentrations of estradiol (pg/ml) (ß=-15.6%, 95% confidence interval (CI): -26.5%, -3.2%) and inhibin B (pg/ml) (ß=-20.3%, CI: -35.1%, -2.3%), and higher mean concentrations of FSH (IU/I) (ß=12.2%, CI: -1.5%, 27.9%) and LH (IU/I) (ß=10.4%, CI: -7.2%, 31.3%), than unexposed women. ORs for the association of DES with maximum FSH>10 IU/I and minimum inhibin B<45 pg/ml--indicators of low ovarian reserve--were 1.90 (CI: 0.86, 4.22) and 4.00 (CI: 0.88-18.1), respectively. Prenatal DES exposure was associated with variation in concentrations of FSH, estradiol and inhibin B among women of late reproductive age.

Excess melanoma incidence in a cohort exposed to high levels of environmental selenium.

Epidemiological studies on the relation between selenium and human cancer have yielded strongly conflicting results. Prompted by the observation of a positive association between selenium intake and site-specific cancers, including melanoma, in a large cohort of nurses, we studied the 11-year melanoma incidence in an Italian cohort that consumed unusually high levels of inorganic selenium in tap water from 1975 to 1985. The setting was Reggio Emilia, an Italian municipality that provided a natural experiment relating to intake of high levels of inorganic selenium. We identified 2,065 individuals with high selenium exposure, who contributed a total of 20,179 person-years of follow-up, and we compared their experience with the 1,384,386 person-years of follow-up in the remaining population of Reggio Emilia. We included all cases of pathologically confirmed malignant melanoma, including intraocular melanoma, identified from the Reggio Emilia Hospital, the Bologna regional registry of hospital discharges, and the Milan National Cancer Institute. Eight cases of malignant melanoma occurred in the exposed cohort during the follow-up. Melanoma incidence was 3.9 times greater in the exposed than in the unexposed cohort (95% exact confidence limits, 1.8-7.4).