GAA variants and phenotypes among 1,079 patients with Pompe disease: Data from the Pompe Registry.

Identification of variants in the acid α-glucosidase (GAA) gene in Pompe disease provides valuable insights and systematic overviews are needed. We report on the number, nature, frequency, and geographic distribution of GAA sequence variants listed in the Pompe Registry, a long-term, observational program and the largest global repository of Pompe disease data. Variant information was reviewed and compared with publicly available GAA databases/resources. Among 1,079 eligible patients, 2,075 GAA variants (80 unique novel) were reported. Variants were listed by groups representing Pompe disease phenotypes. Patients were classified as Group A: Symptom onset ≤ 12 months of age with cardiomyopathy; Group B: Symptom onset ≤ 12 years of age (includes patients with symptom onset ≤ 12 months of age without cardiomyopathy); or Group C: Symptom onset > 12 years of age. Likely impact of novel variants was predicted using bioinformatics algorithms. Variants were classified by pathogenicity using ACMG guidelines. Data reported from the Pompe Registry provide new information about the distribution of GAA variants globally and across the clinical spectrum, add to the number and diversity of GAA variants registered in public databases through published data sharing, provide a first indication of the severity of novel variants, and assist in diagnostic practice and outcome prediction.

Time to treatment benefit for adult patients with Fabry disease receiving agalsidase ß: data from the Fabry Registry.

BACKGROUND: Agalsidase ß is a form of enzyme replacement therapy for Fabry disease, a genetic disorder characterised by low α-galactosidase A activity, accumulation of glycosphingolipids and life-threatening cardiovascular, renal and cerebrovascular events. In clinical trials, agalsidase ß cleared glycolipid deposits from endothelial cells within 6 months; clearance from other cell types required sustained treatment. We hypothesised that there might be a 'lag time' to clinical benefit after initiating agalsidase ß treatment, and analysed the incidence of severe clinical events over time in patients receiving agalsidase ß. METHODS: The incidence of severe clinical events (renal failure, cardiac events, stroke, death) was studied in 1044 adult patients (641 men, 403 women) enrolled in the Fabry Registry who received agalsidase ß (average dose 1 mg/kg every 2 weeks) for up to 5 years. RESULTS: The incidence of all severe clinical events was 111 per 1000 person-years (95% CI 84 to 145) during the first 6 months. After 6 months, the incidence decreased and remained stable within the range of 40-58 events per 1000 patient-years. The largest decrease in incidence rates was among male patients and those aged ≥40 years when agalsidase ß was initiated. CONCLUSIONS: Contrary to the expected increased incidence of severe clinical events with time, adult patients with Fabry disease had decreased incidence of severe clinical events after 6 months treatment with agalsidase ß 1 mg/kg every 2 weeks. TRIAL REGISTRATION NUMBER: NCT00196742.

Current needs in pediatric pharmacoepidemiology.

PURPOSE: We report on a needs assessment conducted by the International Society of Pharmacoepidemiology (ISPE) Pediatric Special Interest Group (SIG) to identify critical needs in pediatric pharmacoepidemiology and directions for future activities. METHODS: A mixed methods survey using a structured interview was conducted in the SIG and ISPE membership to elicit information about current activities in pediatric pharmacoepidemiology and identify critical methodologic issues. The interviews were conducted in two phases over 2013 and 2014, beginning with interviews of SIG members and expanding to the wider ISPE membership. Members of the SIG conducted the interviews and summarized the responses. RESULTS: Twenty-nine ISPE members participated in the needs assessment The respondents reported working with a total of 59 distinct databases, with only eight databases used by more than one respondent. Seventeen respondents (57%) reported issues of limited sample sizes, noting that the problem intensifies when studying age sub-groups or specific genetic populations. Missing data elements were a problem in three main areas: lack of detailed medication information, inability to link to parental data, and lack of detailed information about age. Respondents reported the need for data elements not typically required in studies of adults, such as birthweight and current height and weight, as well as school performance and mental health status. CONCLUSIONS: Our needs assessment describes a preliminary picture of the emerging sub-specialty of pediatric pharmacoepidemiology encompassing a range of age sub-groups, disease areas, and medical specialties. The assessment also documents a body of methodologic challenges unique to pharmacoepidemiologic research in children. Copyright © 2016 John Wiley & Sons, Ltd.

Epidemiology of moderately severe and severe non-proliferative diabetic retinopathy in South West England.

AIMS: To estimate the incidence of early treatment diabetic retinopathy study (ETDRS) level 47 and 53 and progression to treatment with panretinal photocoagulation (PRP) for proliferative DR (PDR). METHODS: Log-linear regression was used to estimate the incidence of level 47-53 or worse for 33,009 people with diabetes (PWD) in Gloucestershire during 2013-2016 by calendar year and diabetes type, based on the first recording. Progression was analysed in Gloucestershire and Bristol with a parametric survival analysis examining the association of baseline and time-varying demographic and clinical factors on time to PRP after the first recording of level 47-53. RESULTS: Incidence decreased from 0.57 (95% confidence intervals (CI) 0.48-0.67) per 100 PWD in 2013 to 0.35 (95% CI 0.29-0.43) in 2016 (p < 0.001). For progression, 338 eligible PWD from Gloucestershire and 418 from Bristol were followed for a median of 1.4 years; 78 and 83% had Type 2 diabetes and a median (interquartile range) of 15 (10-22) and 17 (11-25) years duration of diagnosed diabetes respectively. Three years from the incident ETDRS 47-53, 18.9% and 17.2% had received PRP respectively. For Gloucestershire, severe IRMA and updated mean HbA1c were associated with an increase in the risk of initiating PRP (hazard ratio 3.14 (95% CI: 1.60-6.15) and 1.21 (95% CI: 1.06-1.38 per 10 mmol/mol) respectively). CONCLUSION: This study provides additional understanding of this population and shows that a high proportion of patients with ETDRS levels 47-53 need to be monitored as they are at high risk of progressing to PDR.

Prevalence and incidence of diabetic retinopathy (DR) in the UK population of Gloucestershire.

PURPOSE: To estimate prevalence and incidence of diabetic retinopathy (DR) in a UK region by severity between 2012 and 2016 and risk factors for progression to proliferative DR (PDR). METHODS: Electronic medical records from people with diabetes (PWD) ≥18 years seen at the Gloucestershire Diabetic Eye Screening Programme (GDESP) and the hospital eye clinic were analysed (HEC). Prevalence and incidence of DR per 100 PWD (%) by calendar year, grade and diabetes type were estimated using log-linear regression. Progression to PDR and associated risk factors were estimated using parametric survival analyses. RESULTS: Across the study period, 35 873 PWD had at least one DR assessment. They were aged 66 (56-75) years (median (interquartile range)), 57% male, 5 (1-10) years since diabetes diagnosis, 93% Type 2 diabetes. Prevalence of DR decreased from 38.9% (95% CI: 38.1%, 39.8%) in 2012 to 36.6% (95% CI: 35.9%, 37.3%) in 2016 (p < 0.001). Incidence of any DR decreased from 10.9% (95% CI: 10.4%, 11.5%) in 2013 to 8.5% (95% CI: 8.1%, 9.0%) in 2016 (p < 0.001). Prevalence of PDR decreased from 3.5% (95% CI: 3.3%, 3.8%) in 2012 to 3.1% (95% CI 2.9%, 3.3%) in 2016 (p = 0.008). Incidence of PDR did not change over time. HbA1c and bilateral moderate-severe NPDR were statistically significant risk factors associated with progression to PDR. CONCLUSIONS: Incidence and prevalence of DR decreased between 2012 and 2016 in this well-characterized population of the UK.

Dietary and demographic correlates of serum beta-glucuronidase activity.

beta-glucuronidase, an acid hydrolase that deconjugates glucuronides, may increase cancer risk; however, little is known about factors associated with human beta -glucuronidase. Our objective was to examine whether dietary and demographic factors were associated with serum beta -glucuronidase activity. We conducted a cross-sectional study among 279 healthy men and women aged 20 to 40 yr. Diet, categorized by botanical families and nutrient intakes, was assessed from 3-day food records and a validated semiquantitative food frequency questionnaire. Demographic factors were directly measured or self-reported. Adjusted mean beta -glucuronidase activity across categories of exposure variables were calculated by multiple linear regression. Higher beta -glucuronidase activity was significantly associated with being male, older age (> or = 30 yr), non-Caucasian, overweight (> or = 25 kg/m(2)), and higher intakes of gamma-tocopherol. Conversely, lower beta -glucuronidase activity was significantly associated with higher intakes of calcium, iron, and magnesium. A suggestive decrease in beta -glucuronidase activity was observed for the botanical families Cruciferae, Rutaceae, Compositae, Roseaceae, and Umbelliferae, but tests for trend were not statistically significant. In conclusion, several dietary and nondietary factors were associated with beta -glucuronidase activity; however, confirmation of these associations are needed.

Respiratory function during enzyme replacement therapy in late-onset Pompe disease: longitudinal course, prognostic factors, and the impact of time from diagnosis to treatment start.

OBJECTIVE: To examine respiratory muscle function among late-onset Pompe disease (LOPD) patients in the Pompe Registry (NCT00231400/Sanofi Genzyme) during enzyme replacement therapy (ERT) with alglucosidase alfa by assessing the longitudinal course of forced vital capacity (FVC), prognostic factors for FVC, and impact of time from diagnosis to ERT initiation. METHODS: Longitudinal FVC data from LOPD (symptom onset > 12 months or ≤ 12 months without cardiomyopathy) patients were analyzed. Patients had to have baseline FVC (percent predicted upright) assessments at ERT start and ≥ 2 valid post-baseline assessments. Longitudinal analyses used linear mixed-regression models. RESULTS: Among 396 eligible patients, median baseline FVC was 66.9% (range 9.3-126.0). FVC remained stable during the 5-year follow-up (slope = - 0.17%, p = 0.21). Baseline FVC was lower among various subgroups, including patients who were male; older at ERT initiation; had a longer duration from symptom onset to ERT initiation; and had more advanced disease at baseline (based on respiratory support use, inability to ambulate, ambulation device use). Age at symptom onset was not associated with baseline degree of respiratory dysfunction. Differences between subgroups observed at baseline remained during follow-up. Shorter time from diagnosis to ERT initiation was associated with higher FVC after 5 years in all patients and the above subgroups using a cut-off of 1.7 years. CONCLUSION: FVC stability over 5 years suggests that respiratory function is preserved during long-term ERT in real-world settings. Early initiation of alglucosidase alfa was associated with preservation of FVC in LOPD patients with better respiratory function at the time of treatment initiation.

MTHFR C677T and postmenopausal breast cancer risk by intakes of one-carbon metabolism nutrients: a nested case-control study.

INTRODUCTION: The C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene has been hypothesized to increase breast cancer risk. However, results have been inconsistent, and few studies have reported the association by menopausal status or by intakes of nutrients participating in one-carbon metabolism. Our aims were to investigate whether MTHFR C677T was associated with postmenopausal breast cancer risk and whether this relation was modified by intakes of folate, methionine, vitamins B(2), B(6), and B(12), and alcohol. METHODS: We studied 318 incident breast cancer cases and 647 age- and race-matched controls participating in a nested case-control study of postmenopausal women within the VITamins And Lifestyle (VITAL) cohort. Genotyping was conducted for MTHFR C677T and dietary and supplemental intakes were ascertained from a validated questionnaire. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression. RESULTS: We observed a 62% increased risk of breast cancer among postmenopausal women with the TT genotype (OR = 1.62; 95% CI: 1.05 to 2.48). Women with a higher number of variant T alleles had higher risk of breast cancer (P for trend = 0.04). Evidence of effect-modification by intakes of some B vitamins was observed. The most pronounced MTHFR-breast cancer risks were observed among women with the lowest intakes of dietary folate (P for interaction = 0.02) and total (diet plus supplemental) vitamin B(6) (P for interaction = 0.01), with no significant increased risks among women with higher intakes. CONCLUSIONS: This study provides support that the MTHFR 677TT genotype is associated with a moderate increase in risk of postmenopausal breast cancer and that this risk may be attenuated with high intakes of some one-carbon associated nutrients.

Physical activity and premenopausal breast cancer: an examination of recall and selection bias.

BACKGROUND: Compared with cohort studies, case-control investigations have tended to report clearer protective associations for the relationship between physical activity and premenopausal breast cancer risk. METHODS: We conducted a case-control study within the Nurses' Health Study II cohort to examine whether recall or selection bias could explain the stronger protective associations. Self-reported total recreational physical activity during adulthood and over a woman's lifetime (ages 12 years to current) were assessed in 1997 before diagnosis and, again, from one to seven years after breast cancer diagnosis among the same women. RESULTS: Eighty-seven percent of cases (417 of 479) and 82% of controls (390 of 474) responded. Selection bias was observed for activity during adulthood but not for activity over a woman's lifetime. Recall bias was not observed in the direction we expected: the odds ratios (ORs) for breast cancer comparing the highest versus lowest quintile of prospectively reported total activity were not significantly different than the corresponding estimates from retrospective reports (e.g., lifetime activity: prospective OR = 0.58, 95% CI: 0.37, 0.93 versus retrospective OR = 0.80; 95% CI: 0.50, 1.29). CONCLUSION: Recall or selection bias may not have been accounted for protective associations among case-control investigations examining lifetime recreational physical activity and breast cancer. Selection bias related to recreational physical activity during adulthood and random error in the measurement of physical activity remain concerns.

A prospective study of bowel motility and related factors on breast cancer risk.

BACKGROUND: Estrogen is an established risk factor for breast cancer. Greater bowel motility has been associated with increased estrogen excretion and lower serum estrogen levels, suggesting that it may influence breast cancer risk. However, only one other epidemiologic study thus far, to our knowledge, has examined the relation between bowel motility and breast cancer risk. METHODS: We prospectively examined whether bowel motility, measured by self-reported frequency of bowel movements, and related factors (constipation, laxative use, water consumption, and dietary fiber intake) were associated with incidence of breast cancer among 28,586 postmenopausal women, ages 50 to 76 years, in the Vitamins and Lifestyle study. Cox proportional hazards models were used to estimate multivariate-adjusted relative risks (RR) and 95% confidence intervals (95% CI). From 2000 to 2005, 507 incident invasive breast cancers among the cohort were identified. RESULTS: Women with very frequent (> or =3/d) bowel movements had a 46% decreased risk compared with 1/d women (RR, 0.54; 95% CI, 0.31-0.92), but the test for linear trend was not significant (P(trend) = 0.41). Constipation was nonsignificantly associated with increased risk (RR, 1.30 for > or =1/wk versus <1/y; 95% CI, 0.87-1.95). No statistically significant associations were observed for the other study exposures: 10-year chemical laxative use, 10-year use of fiber laxatives, water consumption, and dietary fiber intake. CONCLUSION: This study adds limited support to the hypothesis that increased bowel motility lowers breast cancer risk.

Serum beta-glucuronidase activity in response to fruit and vegetable supplementation: a controlled feeding study.

BACKGROUND: Fruit and vegetable (F&V) intake may lower the risk of some cancers. One hypothesized, but understudied, chemopreventive mechanism is that plant food constituents inhibit beta-glucuronidase, an acid hydrolase that deconjugates glucuronides. METHODS: We conducted a crossover feeding trial in 63 healthy women and men ages 20 to 40 years to examine the effect of diet on serum beta-glucuronidase activity. Participants were randomized to two 2-week experimental diets with an intervening washout period: a diet high in selected citrus fruit, crucifers, and soy (F&V) and a diet devoid of fruits, vegetables, and soy (basal). Serum beta-glucuronidase activity was measured during the preintervention, F&V, and basal periods. Linear mixed models were used to obtain effect estimates and 95% confidence intervals (95% CI). RESULTS: We observed statistically significantly higher beta-glucuronidase activity during the F&V than the basal diet (ratio, F&V versus basal diet, 1.09; 95% CI, 1.05-1.13; P < 0.01). These results were probably due to decreased beta-glucuronidase activity during the basal diet (ratio, basal period versus preintervention, 0.93; 95% CI, 0.87-0.98; P = 0.01) rather than increased enzyme activity during the F&V diet (ratio, F&V period versus preintervention, 1.01; 95% CI, 0.96-1.06; P = 0.64). Response to the experimental diet did not differ by sex (P(interaction) = 0.30), but there was a suggestion of a short-term diet effect at 8 versus 15 days (P(interaction) = 0.06). CONCLUSION: This intervention of selected F&V did not lower beta-glucuronidase activity. Further investigation is needed regarding what other foods and phytochemicals may influence beta-glucuronidase activity and effect modifiers of this relation.

Folate and one-carbon metabolism nutrients from supplements and diet in relation to breast cancer risk.

BACKGROUND: Few epidemiologic studies have examined very high intakes of folate and whether consumption of nutrients involved in one-carbon metabolism is associated with breast cancer risk. OBJECTIVE: We prospectively examined whether the consumption of folate and nutrients involved in one-carbon metabolism (methionine, riboflavin, and vitamins B-6 and B-12) from self-reported intakes of diet (in year before baseline) and supplements (averaged over 10 y before baseline) were associated with the incidence of breast cancer and breast cancer tumor characteristics. DESIGN: Participants were 35,023 postmenopausal women aged 50-76 y in the VITamins And Lifestyle (VITAL) cohort study; breast cancer was diagnosed in 743 of these women between baseline (2000-2002) and 2006. Cox proportional hazards models were used to estimate multivariable-adjusted relative risks (RRs) and 95% CIs. RESULTS: Women consuming > or =1272 dietary folate equivalents (DFE)/d of total folate (10-y average) had a 22% decrease in breast cancer risk compared with women consuming < or =345 DFE/d (RR: 0.78; 95% CI: 0.61, 0.99; P for trend = 0.05). A greater benefit was observed for estrogen-receptor (ER) negative than for ER+ breast cancers (RR: 0.38; 95% CI: 0.18, 0.80; P for trend = 0.02; P = 0.02 for the difference between ER- and ER+). Neither current intakes of folate nor current or long-term intakes of other one-carbon nutrients were significantly associated with breast cancer risk. Multivitamin use attenuated the increased risk of breast cancer associated with alcohol drinking (P for interaction = 0.02). CONCLUSIONS: Our study of predominantly supplement users suggests that high intakes of folate averaged over 10 y do not increase breast cancer risk, but may be protective, particularly against ER- breast cancers.

A cohort study of vitamin D intake and melanoma risk.

Data suggest that vitamin D intake may have chemopreventive efficacy against melanoma, but there have been no published epidemiologic studies examining the association between vitamin D intake and melanoma risk in a large prospective cohort. We examined whether dietary and supplemental vitamin D intake was associated with melanoma risk among 68,611 men and women who were participants of the Vitamins and Lifestyle cohort study. Participants reported dietary vitamin D intake over the past year and 10-year use of multivitamin and individual vitamin D supplements on a baseline questionnaire. After follow-up through 2006, 455 incident melanomas were identified through linkage to the Surveillance, Epidemiology, and End Results cancer registry. Cox proportional hazards regression models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for vitamin D intake after adjustment for melanoma risk factors. Compared with the lowest quartile, we did not detect a risk reduction of melanoma in the highest quartiles of dietary vitamin D intake (RR=1.31, CI=0.94-1.82), 10-year average supplemental vitamin D intake (RR=1.13, CI=0.89-1.43), or combined dietary and supplemental intake (1.05, CI=0.79-1.40). In this large prospective cohort, we did not find an association between vitamin D intake and melanoma risk.

Antioxidant supplementation and risk of incident melanomas: results of a large prospective cohort study.

OBJECTIVE: To examine whether antioxidant supplement use is associated with melanoma risk in light of recently published data from the Supplementation in Vitamins and Mineral Antioxidants (SUVIMAX) study, which reported a 4-fold higher melanoma risk in women randomized to receive a supplement with nutritionally appropriate doses of antioxidants. DESIGN: Population-based prospective study (Vitamins and Lifestyle [VITAL] cohort). SETTING: Western Washington State. PARTICIPANTS: A total of 69 671 men and women who self-reported (1) intake of multivitamins and supplemental antioxidants, including selenium and beta carotene, during the past 10 years and (2) melanoma risk factors on a baseline questionnaire. Main Outcome Measure Incident melanoma identified through linkage to the Surveillance, Epidemiology, and End Results (SEER) cancer registry. RESULTS: Cox proportional hazards regression models were used to estimate multivariable relative risks (RRs) and 95% confidence intervals (CIs) for multivitamin, supplemental selenium, and supplemental beta carotene use. After adjusting for melanoma risk factors, we did not detect a significant association between multivitamin use and melanoma risk in women (RR, 1.14; 95% CI, 0.78-1.66) or in men (RR, 1.09; 95% CI, 0.83-1.43). Moreover, we did not observe increased melanoma risk with the use of supplemental beta carotene (RR, 0.87; 95% CI, 0.48-1.56) or selenium (RR, 0.98; 95% CI, 0.69-1.41) at doses comparable with those of the SUVIMAX study. Conclusion Antioxidants taken in nutritional doses do not seem to increase melanoma risk.

Adolescent physical activity and endometriosis risk.

BACKGROUND: In the one study examining the relationship, adolescent physical activity was not associated with risk for endometriosis. Case-control studies have shown 40-80% reductions in risk for adult activity, while only an 11% reduction in endometriosis risk was observed in a recent prospective analysis. METHODS: Using data collected from the Nurses' Health Study II, a prospective cohort study of premenopausal US nurses that began in 1989, we have attempted to clarify this relation. Data are updated every 2 yrs with follow-up for these analyses through to 2001. Women reported the average amount of time per week spent in moderate and strenuous recreational activity during three age periods: ages 12-13, ages 14-17, and ages 18-22. A metabolic equivalent (MET) score was assigned to each activity and these were summed to estimate total activity. RESULTS: During 637,747 person-years of follow-up, 1,481 cases of laparoscopically confirmed endometriosis were reported among women with no past infertility. After adjusting for age, calendar time, birth weight, age at menarche, parity, oral contraceptive use, and body mass index (BMI), we observed a 16% increase in the risk for endometriosis comparing the greatest amount of activity (≥80 MET-h/wk) with the least (<20 MET-h/wk) during ages 12-13 (RR=1.16, 95% CI=0.98-1.37, p-value test for trend=0.02), and no associations for ages 14-17 or ages 18-22. In analyses of the individual activity types within each time period, only strenuous activity during ages 12-13 was associated with endometriosis. CONCLUSIONS: We did not find evidence of a beneficial association between adolescent physical activity and laparoscopically confirmed endometriosis, but in fact found a small increase in risk.

A large cohort study of nonsteroidal anti-inflammatory drug use and melanoma incidence.

Results of laboratory studies indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) may have chemopreventive activity and therapeutic efficacy against melanoma. However, few published epidemiological studies have examined the association between NSAID use and melanoma risk. We examined whether NSAID use was associated with melanoma risk among 63 809 men and women in the Vitamins and Lifestyle (VITAL) cohort study. Participants self-reported NSAID use (low-dose aspirin, regular or extra-strength aspirin, and nonaspirin NSAIDs) during the previous 10 years and data related to their melanoma risk factors on a baseline questionnaire. After linkage of the VITAL database to the NCI Surveillance, Epidemiology, and End Results cancer registry, 349 patients with incident melanoma were identified through December 31, 2005. Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of melanoma by NSAID use as categorized by overall use, duration of use, and dose (expressed as average number of days of use during the past 10 years). All statistical tests were two-sided. After adjusting for melanoma risk factors and indications for NSAID use, no association between NSAID use and melanoma risk was found. When use of at least 4 d/wk was compared with nonuse, no melanoma risk reduction was detected for any NSAID dose (HR = 1.12, 95% CI = 0.84 to 1.48), for any NSAID excluding low-dose aspirin (HR = 1.03, 95% CI = 0.74 to 1.43), for regular- or extra-strength aspirin (HR = 1.10, 95% CI = 0.76 to 1.58), or for nonaspirin NSAIDs (HR = 1.22, 95% CI = 0.75 to 1.99). Moreover, NSAID use was not associated with tumor invasion (P(interaction) = .38), tumor thickness (P(trend) = .98), or risk of metastasis (HR = 1.09, 95% CI = 0.32 to 3.62). NSAIDs do not appear to be good candidates for the chemoprevention of melanoma.

A prospective study of age-specific physical activity and premenopausal breast cancer.

BACKGROUND: Physical activity has been consistently associated with lower risk of postmenopausal breast cancer, but its relationship with premenopausal breast cancer is unclear. We investigated whether physical activity is associated with reduced incidence of premenopausal breast cancer, and, if so, what age period and intensity of activity are critical. METHODS: A total of 64,777 premenopausal women in the Nurses' Health Study II reported, starting on the 1997 questionnaire, their leisure-time physical activity from age 12 to current age. Cox regression models were used to examine the relationship between physical activity, categorized by age period (adolescence, adulthood, and lifetime) and intensity (strenuous, moderate, walking, and total), and risk of invasive premenopausal breast cancer. RESULTS: During 6 years of follow-up, 550 premenopausal women developed breast cancer. The strongest associations were for total leisure-time activity during participants' lifetimes rather than for any one intensity or age period. Active women engaging in 39 or more metabolic equivalent hours per week (MET-h/wk) of total activity on average during their lifetime had a 23% lower risk of premenopausal breast cancer (relative risk = 0.77; 95% confidence interval = 0.64 to 0.93) than women reporting less activity. This level of total activity is equivalent to 3.25 h/wk of running or 13 h/wk of walking. The age-adjusted incidence rates of breast cancer for the highest (> or = 54 MET-h/wk) and lowest (< 21 MET-h/wk) total lifetime physical activity categories were 136 and 194 per 100 000 person-years, respectively. High levels of physical activity during ages 12-22 years contributed most strongly to the association. CONCLUSIONS: Leisure-time physical activity was associated with a reduced risk for premenopausal breast cancer in this cohort. Premenopausal women regularly engaging in high amounts of physical activity during both adolescence and adulthood may derive the most benefit.

Validation of adolescent diet recalled by adults.

BACKGROUND: Few studies have examined the validity of adolescent diet as recalled by adults many years later. METHODS: In this investigation, we examined the validity of a 124-item food frequency questionnaire (HS-FFQ) completed by 80 young adults in the United States about their diet during high school. We compared the HS-FFQ with 3 24-hour recalls and 2 food-frequency questionnaires (YAQ) collected 10 years earlier in 1993, when the participants were in high school. We calculated Pearson correlation coefficients for 20 to 25 nutrients and corrected these correlations for within-person variation. RESULTS: The average corrected correlation for energy-adjusted nutrient intakes calculated from the HS-FFQ and the 24-hour recalls was 0.45 (range = 0.16-0.68). The mean corrected correlation between the HS-FFQ and YAQs was 0.58 (range = 0.40-0.88). CONCLUSION: Taken together with the results of our earlier work, this analysis suggests that the HS-FFQ can reasonably capture adolescent diet recalled by young adults.

Adult recall of adolescent diet: reproducibility and comparison with maternal reporting.

Many cancers have long latency periods, and dietary factors in adolescence may plausibly affect cancer occurrence in adulthood. Because of a lack of prospective data, retrospective collection of data on adolescent diet is essential. The authors evaluated a 124-item high school food frequency questionnaire (HS-FFQ) assessing diet during high school (15-35 years in the past) that was completed in 1998 by 45,947 US women in the Nurses' Health Study II (NHSII) cohort. To assess reproducibility, the authors readministered the HS-FFQ approximately 4 years later to 333 of these women. The mean Pearson correlation for 38 nutrient intakes was 0.65 (range, 0.50-0.77), and the mean Spearman rank correlation for food intakes was 0.60 (range, 0.37-0.77). Current adult diet was only weakly correlated with recalled adolescent diet (for nutrient intakes, mean r = 0.20). For assessment of validity, 272 mothers of the NHSII participants were asked to report information on their daughters' adolescent diets using the HS-FFQ. In this comparison, the mean Pearson correlation was 0.40 (range, 0.13-0.59) for nutrients, and the mean Spearman rank correlation for foods was 0.30 (range, 0.10-0.61). While further studies are warranted, these findings imply that this food frequency questionnaire provides a reasonable record of adolescent diet.