Iodine Nutrition in Children ≤2 years of Age in Norway.

BACKGROUND: As a component of the thyroid hormones (THs), iodine is vital for normal neurodevelopment during early life. However, both deficient and excess iodine may affect TH production, and data on iodine status in young children are scarce. OBJECTIVES: To describe iodine nutrition (iodine status and intake) in children ≤2 y of age in Innlandet County (Norway) and to describe the associations with maternal iodine nutrition. METHODS: A cross-sectional study was performed in a representative sample of mother-child pairs selected from 30 municipalities from November 2020 until October 2021. Iodine status [child urinary iodine concentration (UIC), maternal UIC, and breast milk iodine concentration (BMIC)] was measured. Child's iodine intake was estimated using 2 24-h dietary recalls (24-HR) and a food frequency questionnaire. The Multiple Source Method was used to estimate the usual iodine intake distributions from the 24-HR assessments. RESULTS: The median UIC in 333 children was 145 µg/L, indicating adequate iodine status according to the WHO cutoff (100 µg/L). The median usual iodine intake was 83 µg/d. Furthermore, 35% had suboptimal usual iodine intakes [below the proposed Estimated average requirement (72 µg/d)], whereas <1% had excessive usual iodine intakes [above the Upper intake level (200 µg/d)]. There was a positive correlation between children's iodine intake and BMIC (Spearman rank correlation coefficient r = 0.67, P < 0.001), and between children's UIC and BMIC (r = 0.43, P < 0.001), maternal UIC (r = 0.23, P = 0.001), and maternal iodine intake (r = 0.20, P = 0.004). CONCLUSION: Despite a median UIC above the cutoff for iodine sufficiency, more than a third of the children had suboptimal usual iodine intakes. Our findings suggest that many children will benefit from iodine fortification and that risk of iodine excess in this age group is low.

Inadequate Iodine Intake in Mothers of Young Children in Innlandet County, Norway.

Background: Iodine has an essential role in child growth and brain development. Thus, sufficient iodine intake is particularly important in women of childbearing age and lactating women. Objectives: This cross-sectional study aimed to describe iodine intake in a large random sample of mothers of young children (aged ≤2 y) living in Innlandet County, Norway. Methods: From November 2020 to October 2021, 355 mother-child pairs were recruited from public health care centers. Dietary data were obtained using two 24-h dietary recalls (24-HRs) per woman and an electronic FFQ. The Multiple Source Method was used to estimate the usual iodine intake from the 24-HR assessment. Results: Based on the 24-HRs, the median (P25, P75) usual iodine intake from food was 117 µg/d (88, 153) in nonlactating women and 129 µg/d (95, 176) in lactating women. The median (P25, P75) total usual iodine intake (from food combined with supplements) was 141 µg/d (97, 185) in nonlactating women and 153 µg/d (107, 227) in lactating women. Based on the 24-HRs, 62% of the women had a total iodine intake below the recommendations (150 µg/d in nonlactating women and 200 µg/d in lactating women), and 23% of them had an iodine intake below the average requirement (100 µg/d). The reported use of iodine-containing supplements was 21.4% in nonlactating women and 28.9% in lactating women. In regular users of iodine-containing supplements (n = 63), supplements contributed to an average of 172 µg/d of iodine. Among regular iodine supplement users, 81% reached the recommendations compared with 26% of nonsupplement users (n = 237). The iodine intake estimated by FFQ was substantially higher than that estimated by 24-HRs. Conclusions: Maternal iodine intake in Innlandet County was inadequate. This study confirms the need for action to improve iodine intake in Norway, particularly among women of childbearing age.

Births in freestanding midwifery-led units in Norway: What women view as important aspects of care.

OBJECTIVE: To describe what women view as important aspects of care when giving birth in freestanding midwifery-led units in Norway. METHODS: Data from four open-ended questions in the Babies Born Better survey, Version 1, 2 and 3 was used. We performed inductive content analysis to explore and describe women's experiences with the care they received. RESULTS: In all, 190 women who had given birth in midwifery-led units in Norway between 2010 and 2020 responded to the B3 survey. The final sample comprised 182 respondents. The analysis yielded three main categories: 1) The immediate birth surroundings, 2) Personal and safe support, and 3) Organisational conditions. CONCLUSION: This study adds valuable knowledge regarding what women describe as important aspects of care in free-standing midwifery-led units. Women experience maternity services in these units as peaceful, flexible and family-friendly. However, some women perceive the freestanding midwifery-led unit as a vulnerable service, mainly due to lack of midwives on call and uncertainty around temporary closure of the freestanding midwifery-led units. This finding points to the importance of staffing of birth facilities to ensure that all women giving birth have available midwifery care at all times, which is recommended in the National guidelines for care during labour and birth. Predictability around place of birth for the upcoming birth is crucial for every woman and her family. These goals might be achieved by a stable, continuous maternity service in all geographical areas of the country.

Vitamin B12 status in infancy and the effect of a vitamin B12 injection in infants with subclinical vitamin B12 deficiency: study protocol for a register-based randomised controlled trial.

INTRODUCTION: Vitamin B12 (cobalamin) is crucial for optimal child development and growth, yet deficiency is common worldwide. The aim of this study is twofold; (1) to describe vitamin B12 status and the status of other micronutrients in Norwegian infants, and (2) in a randomised controlled trial (RCT), investigate the effect of vitamin B12 supplementation on neurodevelopment in infants with subclinical vitamin B12 deficiency. METHODS AND ANALYSIS: Infant blood samples, collected at public healthcare clinics, are analysed for plasma cobalamin levels. Infants with plasma cobalamin <148 pmol/L are immediately treated with hydroxocobalamin and excluded from the RCT. Remaining infants (cobalamin ≥148 pmol/L) are randomly assigned (in a 1:1 ratio) to either a screening or a control group. In the screening group, baseline samples are immediately analysed for total homocysteine (tHcy), while in the control group, the baseline samples will be analysed after 12 months. Screening group infants with plasma tHcy >6.5 µmol/L, are given an intramuscular injection of hydroxocobalamin (400 µg). The primary outcomes are cognitive, language and motor development assessed using the Bayley Scales of Infant and Toddler Development at 12 months of age. ETHICS AND DISSEMINATION: The study has been approved by the Regional Committee for Medical and Health Research Ethics (ref: 186505). Investigators who meet the Vancouver requirements will be eligible for authorship and be responsible for dissemination of study findings. Results will extend current knowledge on consequences of subclinical vitamin B12 deficiency during infancy and may inform future infant feeding recommendations. TRIAL REGISTRATION NUMBER: NCT05005897.

Modifiable and non-modifiable risk factors for obstetric anal sphincter injury in a Norwegian Region: a case-control study.

BACKGROUND: Obstetric anal sphincter injury (OASI) is a common and severe complication of vaginal delivery and may have short- and long-term consequences, including anal incontinence, sexual dysfunction and reduced quality of life. The rate of OASI varies substantially between studies and national birth statistics, and a recent meta-analysis concluded that there is a need to identify unrecognized risk factors. Our aim was therefore to explore both potential modifiable and non-modifiable risk factors for OASI. METHODS: We performed a case-control study in a single center maternity clinic in South-Eastern Norway. Data were extracted retrospectively from an institutional birth registry. The main outcome measure was the occurrence of the woman's first-time 3rd or 4th degree perineal lesion (OASI) following singleton vaginal birth after 30 weeks' gestation. For each woman with OASI the first subsequent vaginal singleton delivery matched for parity was elected as control. The study population included 421 women with OASI and 421 matched controls who gave birth during 1990-2002. Potential risk factors for OASI were assessed by conditional logistic regression analyses. RESULTS: The mean incidence of OASI was 3.4% of vaginal deliveries, but it increased from 1.9% to 5.8% during the study period. In the final multivariate regression model, higher maternal age and birthweight for primiparous women, and higher birthweight for the multiparous women, were the only non-modifiable variables associated with OASI. Amniotomy was the strongest modifiable risk factor for OASI in both primi- (odds ratio [OR] 4.84; 95% confidence interval [CI] 2.60-9.02) and multiparous (OR 3.76; 95% CI 1.45-9.76) women, followed by augmentation with oxytocin (primiparous: OR 1.63; 95% CI 1.08-2.46, multiparous: OR 3.70; 95% CI 1.79-7.67). Vacuum extraction and forceps delivery were only significant risk factors in primiparous women (vacuum: OR 1.91; 95% CI 1.03-3.57, forceps: OR 2.37; 95% CI 1.14-4.92), and episiotomy in multiparous women (OR 2.64; 95% CI 1.36-5.14). CONCLUSIONS: Amniotomy may be an unrecognized independent modifiable risk factor for OASI and should be further investigated for its potential role in preventive strategies.

Antenatal thyroid hormone therapy and antithyroid drug use in Norway from 2004 to 2018.

Objective: Thyroid disease during pregnancy is associated with adverse pregnancy outcomes and suboptimal fetal development. During the last decades, guidelines for diagnosing thyroid disease during pregnancy have changed considerably and there has been increased awareness. This study aimed to describe the prevalence of thyroid disease treatment over time among pregnant women in Norway. Design: Nationwide register-based study. Methods: We combined historical data from the Medical Birth Registry of Norway and the Norwegian Prescription Database, identifying pregnant women using thyroid therapy from 2004 to 2018. Results: A total of 855,067 pregnancies were included in the analyses. The proportion of women using thyroid hormone replacement therapy during pregnancy increased from 1.46% (n = 800) in 2004 to 3.57% (n = 1940) in 2018. The proportion of women using antithyroid medications also increased from 0.04% (n = 20) in 2004 to 0.10% (n = 56). During these 15 years, the mean maternal age increased by 0.9 years. When adjusting for age, the risk for being on thyroid hormone replacement therapy during pregnancy increased by an average of 5% per year (odds ratio: 1.05, 95% CI: 1.05-1.05). Conclusion: During the recent 15 years, there has been a substantial increase in the use of thyroid hormone therapy in Norwegian pregnant women. We speculate that this could be due to an increased awareness in combination with overdiagnosis because of inappropriate diagnostic criteria. To truly understand the possible causes and consequences of this development, further research is warranted.

Adequate Urinary Iodine Concentration among Infants in the Inland Area of Norway.

Considering the importance of iodine to support optimal growth and neurological development of the brain and central nervous system, this study aimed to assess and evaluate iodine status in Norwegian infants. We collected data on dietary intake of iodine, iodine knowledge in mothers, and assessed iodine concentration in mother's breast milk and in infant's urine in a cross-sectional study at two public healthcare clinics in the inland area of Norway. In the 130 mother-infant pairs, the estimated infant 24-h median iodine intake was 50 (IQR 31, 78) µg/day. The median infant urinary iodine concentration (UIC) was 146 (IQR 93, 250) µg/L and within the recommended median defined by the World Health Organization for this age group. Weaned infants had a higher UIC [210 (IQR 130, 330) µg/L] than exclusively breastfed infants [130 (IQR 78, 210) µg/L] and partially breastfed infants [135 (IQR 89, 250) µg/L], which suggest that the dietary data obtained in this study did not capture the accurate iodine intake of the included infants. The iodine status of infants in the inland area of Norway seemed adequate. Weaned infants had higher UIC compared to breastfed infants, suggesting early access and consumption of other sources of iodine in addition to breast milk.

Health-Related Behaviors in Adolescents Mediate the Association between Subjective Social Status and Body Mass Index.

The aim of this study was to explore the association between adolescent subjective social status (SSS) and body mass index (BMI) at two different time points and to determine whether this association was mediated by health-related behaviors. In 2002 (n = 1596) and 2017 (n = 1534), tenth-grade students (15-16 years old) in schools in the District of Oppland, Norway, completed a survey. Four categories of perceived family economy were measured as SSS, and structural equation modeling was performed, including a latent variable for unhealthy behavior derived from cigarette smoking, snuff-use, and alcohol-drinking as well as dietary and exercise as mediators. No linear association was found between SSS and BMI in 2002 (standardized ß -0.02, (95% confidence interval (CI) -0.07, 0.03)). However, an association was present in 2017 (standardized ß -0.05 (95% CI -0.10, -0.001)), indicating that BMI decreased by 0.05 standard deviations (0.05 × 3.1 = 0.16 BMI unit) for every one-category increase in SSS. This association was mediated by exercise (standardized ß -0.013 (95% CI -0.02, -0.004) and unhealthy behavior (standardized ß -0.009 (95% CI -0.002, -0.04)). In conclusion, a direct association between SSS and BMI was found in 2017 in this repeated cross-sectional survey of 15-16-year-old Norwegian adolescents. This association was mediated through health-related behavior.

A Cross-Sectional Study of the Relationship Between Mental Health Problems and Overweight and Obesity in Adolescents.

Background: There is a suggested coexistence between obesity and mental health discomfort in adolescence. The objective of this study was to explore if mental health indices covaried with body mass index (BMI) in adolescence and if there were gender-related disparities. Methods: Data were collected in two cross-sectional surveys of 10th-grade students (15 to 16 years old) carried out in 2002 and 2017. The questionnaires included self-reported height and weight, questions covering mental health using the Strengths and Difficulties Questionnaire (SDQ), lifestyle, and sociodemographic variables. We estimated the associations between SDQ subscale scores and BMI and the prevalence of overweight and obesity in linear and logistic multivariable models. We also estimated the extent to which gender modified these associations. Results: BMI was positively associated with peer problems [beta (ß): 0.08, (95% confidence interval 0.01, 0.14)], indicating that for every point increase in peer problems subscore, BMI increased by 0.08 kg/m2. The association between internalizing (i.e., peer and emotional) problems and BMI and conduct problems and BMI was different for boys and girls (p < 0.05 for all effect modifications). Conclusion: In this repeated cross-sectional study across 15 years, we found that peer problems were associated with BMI in Norwegian adolescents. We also found that there is a possibility that adolescent boys and girls report different mental health symptoms related to increased BMI. This finding implicates a need for gender-specific attention when assessing risk factors for increased BMI in adolescents.

Mild to Moderate Iodine Deficiency and Inadequate Iodine Intake in Lactating Women in the Inland Area of Norway.

Breastfed infants are dependent on an adequate supply of iodine in human milk for the production of thyroid hormones, necessary for development of the brain. Despite the importance of iodine for infant health, data on Norwegian lactating women are scarce. We measured iodine intake and evaluated iodine status and iodine knowledge among lactating women. From October to December 2018, 133 mother-infant pairs were recruited in a cross-sectional study through two public health care centers in Lillehammer and Gjøvik. Each of the women provided two human milk specimens, which were pooled, and one urine sample for analysis of iodine concentration. We used 24-hour dietary recall and food frequency questionnaire (FFQ) to estimate short-term and habitual iodine intake from food and supplements. The median (P25, P75) human milk iodine concentration (HMIC) was 71 (45, 127) µg/L-of which, 66% had HMIC <100 µg/L. The median (P25, P75) urinary iodine concentration (UIC) was 80 µg/L (52, 141). The mean (± SD) 24-hour iodine intake and habitual intake was 78 ± 79 µg/day and 75 ± 73 µg/day, respectively. In conclusion, this study confirms inadequate iodine intake and insufficient iodine status among lactating women in the inland area of Norway and medium knowledge awareness about iodine.

The Reliability of Iodine Concentration in Diaper-Retrieved Infant Urine Using Urine Collection Pads, and in Their Mothers' Breastmilk.

Mild to moderate iodine deficiency is common among women of childbearing age. Data on iodine status in infants are sparse, partly due to the challenges in collecting urine. Urinary iodine concentration (UIC) is considered a good marker for recent dietary iodine intake and status in populations. The aim of this study was to investigate the reliability of iodine concentration measured in two spot-samples from the same day of diaper-retrieved infant urine and in their mothers' breastmilk. We collected urine and breastmilk from a sample of 27 infants and 25 mothers participating in a cross-sectional study at two public healthcare clinics in Norway. The reliability of iodine concentration was assessed by calculating the intraclass correlation coefficients (ICC) and the coefficient of variation (CV). The ICC for infants' urine was 0.64 (95% confidence interval (CI) 0.36-0.82), while the ICC for breastmilk was 0.83 (95% CI 0.65-0.92) Similarly, the intraindividual CV for UIC was 0.25 and 0.14 for breastmilk iodine concentration (BIC). Compared to standard methods of collecting urine for measuring iodine concentration, the diaper-pad collection method does not substantially affect the reliability of the measurements.

Emergency cesarean section among women in Robson groups one and three: A comparison study of immigrant and Norwegian women giving birth in a low-risk maternity hospital in Norway.

Researchers have shown that some immigrant groups have an increased risk of emergency cesarean section. The authors' aim was to examine the differences in emergency cesarean section rates among immigrant women in Norway with low obstetric risks by using the Robson classification system. We performed secondary analysis on a Norwegian cohort study, where 10,125 women were classified in Robson groups one and three. Women from East, Southeast, and Central Asia, and from Africa had a higher risk of emergency cesarean section. The Robson classification system was a useful tool in comparing cesarean section rates between immigrant groups and host country populations.

Obstetric Outcomes of First- and Second-Generation Pakistani Immigrants: A Comparison Study at a Low-Risk Maternity Ward in Norway.

This population-based study compares obstetric outcomes of first- and second-generation Pakistani immigrants and ethnic Norwegians who gave birth at the low-risk maternity ward in Baerum Hospital in Norway from 2006 to 2013. We hypothesized that second-generation Pakistani immigrants are more similar to the ethnic Norwegians because of increased acculturation. Outcome measures were labor onset, epidural analgesia, labor dystocia, episiotomy, vaginal/operative delivery, postpartum hemorrhage, preterm birth, birth weight, transfer to a neonatal intensive care unit, and neonatal jaundice. Compared to first-generation Pakistani immigrants, the second-generation reported more health issues before pregnancy, and they had a higher proportion of preterm births compared to Norwegians. Newborns of first-generation immigrants were more often transferred to a neonatal intensive care compared to Norwegian newborns. Few intergenerational differences in the obstetric outcomes were found between the two generations. A high prevalence of consanguinity in second-generation immigrants suggests the maintenance of a traditional Pakistani marriage pattern.

Immigrants from conflict-zone countries: an observational comparison study of obstetric outcomes in a low-risk maternity ward in Norway.

BACKGROUND: Immigrants have higher risks for some adverse obstetric outcomes. Furthermore, refugees are reported to be the most vulnerable group. This study compared obstetric outcomes between immigrant women originating from conflict-zone countries and ethnic Norwegians who gave birth in a low-risk setting. METHODS: This was a population-based study linking the Medical Birth Registry of Norway to Statistics Norway. The study included the first registered birth during the study period of women from Somalia (n = 278), Iraq (n = 166), Afghanistan (n = 71), and Kosovo (n = 67) and ethnic Norwegians (n = 6826) at Baerum Hospital from 2006-2010. Background characteristics and obstetric outcomes of each immigrant group were compared with ethnic Norwegians with respect to proportions and risks calculated by logistic regression models. RESULTS: In total, 7408 women and their births were analyzed. Women from Somalia were most at risk for adverse obstetric outcomes. Compared with ethnic Norwegians, they had increased odds ratios (OR) for emergency cesarean section (OR 1.81, CI 1.17-2.80), postterm birth (OR 1.93, CI 1.29-2.90), meconium-stained liquor (OR 2.39, CI 1.76-3.25), and having a small-for-gestational-age infant (OR 3.97, CI 2.73-5.77). They had a reduced OR for having epidural analgesia (OR 0.40, CI 0.28-0.56) and a large-for-gestational-age infant (OR 0.32, CI 0.16-0.64). Women from Iraq and Afghanistan had increased risk of having a small-for-gestational-age infant with OR of 2.21 (CI 1.36-3.60) and 2.77 (CI 1.42-5.39), respectively. Iraqi women also had reduced odds ratio of having a large-for-gestational-age infant (OR 0.35, CI 0.15-0.83). Women from Kosovo did not differ from ethnic Norwegians in any of the outcomes we tested. CONCLUSIONS: Even in our low-risk maternity ward, women originating from Somalia were at the greatest risk for adverse obstetric outcomes in the compared groups. We could not find the same risk among the other immigrant women, also originating from conflict-zone countries. Several factors may influence these findings, and this study suggests that immigrant women from Somalia need more targeted care during pregnancy and childbirth.

Higher risk for adverse obstetric outcomes among immigrants of African and Asian descent: a comparison study at a low-risk maternity hospital in Norway.

BACKGROUND: Immigrants have higher risks for some adverse obstetric outcomes, and 40 percent of women giving birth at the low-risk maternity ward in Baerum Hospital, Norway, are immigrants. This study compared obstetric outcomes between immigrants and ethnic Norwegians giving birth in a low-risk setting. METHODS: This was a population-based study linking the Medical Birth Registry of Norway to Statistics Norway. The study included the first registered birth during the study period to immigrant and ethnic Norwegian women at Baerum Hospital from 2006 to 2010. The main outcome measures were onset of labor, operative vaginal delivery, cesarean delivery, episiotomy, postpartum bleeding > 500 mL, epidural analgesia, labor dystocia, gestational age, meconium-stained liquor, 5-minute Apgar score, birthweight, and transfer to a neonatal intensive care unit. RESULTS: A total of 11,540 women originating from 141 countries were divided into seven groups. Compared with Norwegians, women from East, Southeast, and Central Asia had increased risk for operative vaginal delivery, postpartum bleeding, and low Apgar score. The African women had increased risk for postterm birth, meconium-stained liquor, episiotomy, operative vaginal delivery, emergency cesarean delivery, postpartum bleeding, low Apgar score, and low birthweight. Women from South and Western Asia had increased risk for low birthweight. CONCLUSION: Obstetric outcomes of immigrants differ significantly from those of Norwegians, even in a low-risk maternity unit. Thus, immigrant women would benefit from more targeted care during pregnancy and childbirth, even in low-risk settings.

GPs' prescription routines and cooperation with other healthcare personnel before and after implementation of multidose drug dispensing.

BACKGROUND: This study addresses GPs' attitudes towards multidose drug dispensing before and after implementation and their perceived experience of how multidose drug dispensing affects prescription and communication routines for patients in the home care services. This study contributes to a method triangulation with two other studies on the introduction of multidose drug dispensing in Trondheim. METHODS: A controlled before-and-after study carried out in Trondheim (intervention) and Tromsø (control). A questionnaire was distributed to all GPs in the two towns in 2005 with a follow-up questionnaire in 2008. RESULTS: The GPs in Trondheim showed a positive attitude to multidose drug dispensing both before and after the implementation. Increased workload was reported, but still the GPs wanted the system to be continued. Most of the GPs reported a better overview of the patients' medication and a supposed reduction in medication errors. The GPs' prescription- and communication routines were changed only for the multidose drug users and not for the other patients in the home care services. CONCLUSIONS: The study supports the results presented in two previous publications according to GPs' positive attitude towards multidose drug dispensing, their better overview of the patients' medications, and improved cooperation with the pharmacy. This study adds to our understanding of prescription routines among GPs and the use of the medication module in the electronic health record.

The risk of breast cancer linked to menopausal hormone therapy.

BACKGROUND: The Norwegian "Women and cancer" study has shown that when combination hormone replacement products were used for more than five years the relative risk of breast cancer was almost tripled. The population attributable risk was 27 %. In a nested case-control study we have updated the risk estimates for hormone replacement therapy in post-menopausal women since 2002. MATERIAL AND METHOD: We selected an age-matched control for each of the 589 women (aged 46-63) who were found in the period 2004-8 to have invasive breast cancer or cancer in situ. These women responded in 2003-6 to a questionnaire on menstruation and the use of hormone replacement therapy. The data from this and earlier questionnaires were compared and analysed using logistical regression. RESULTS: 226 (26 %) of the women were using hormone replacement at the time of the survey. The average time of use was ten years. Current users had a higher risk of breast cancer than never-users: adjusted OR 2.1 (95 % CI 1.5-3.0). The use of combination therapy for more than five years resulted in the highest risk: OR 3.0 (95 % CI 1.9-4.7). Earlier use of oestrogen products did not result in a higher risk. Neither oestradiol nor tibolon caused a statistically significant increase in risk. 232 cases of breast cancer (17 %) in women aged 45-64 could be attributed to the use of hormones. INTERPRETATION: Long-term use of combination products increases the risk of breast cancer. Relative risk estimates have undergone little change since the previous study, but population attributable risk has fallen along with the decline in new users.

Understanding recent trends in incidence of invasive breast cancer in Norway: age-period-cohort analysis based on registry data on mammography screening and hormone treatment use.

OBJECTIVE: To quantify the separate contributions of menopausal hormone treatment and mammography screening activities on trends in incidence of invasive breast cancer between 1987 and 2008. DESIGN: Population study using aggregated data analysed by an extended age-period-cohort model. SETTING: Norway. Population Norwegian women aged 30-90 between 1987 and 2008, including 50,102 newly diagnosed cases of invasive breast cancer. Main outcomes measures Attributable proportions of mammography screening and hormone treatment to recent incidence of invasive breast cancer, and the remaining variation in incidence after adjustment for mammography screening and hormone treatment. RESULTS: The incidence of invasive breast cancer in Norway increased steadily until 2002, levelled off, and then declined from 2006. All non-linear changes in incidence were explained by use of hormone treatment and mammography screening activities, with about similar contributions of each factor. In 2002, when the incidence among women aged 50-69 was highest, an estimated 23% of the cases in that age group could be attributed to mammography screening and 27% to use of hormone treatment. CONCLUSIONS: Changes in incidence trends of invasive breast cancer since the early 1990s may be fully attributed to mammography screening and hormone treatment, with about similar contributions of each factor.

Endogenous sex steroids and risk of cervical carcinoma: results from the EPIC study.

BACKGROUND: Epidemiologic data and animal models suggest that, despite the predominant role of human papillomavirus infection, sex steroid hormones are also involved in the etiology of invasive cervical carcinoma (ICC). METHODS: Ninety-nine ICC cases, 121 cervical intraepithelial neoplasia grade 3 (CIN3) cases and 2 control women matched with each case for center, age, menopausal status and blood collection-related variables, were identified in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Circulating levels of testosterone (T) and estradiol (E(2)); dehydroepiandrosterone sulfate (DHEAS); progesterone (premenopausal women); and sex hormone-binding globulin (SHBG) were measured using immunoassays. Levels of free (f) T and E(2) were calculated from absolute concentrations of T, E(2), and SHBG. Odds ratios (ORs) and 95% confidence intervals (CI) were computed using regularized conditional logistic regression. RESULTS: Among premenopausal women, associations with ICC were observed for fT (OR for highest vs. lowest tertile = 5.16, 95% CI, 1.50-20.1). SHBG level was associated with a significant downward trend in ICC risk. T, E(2), fE(2), and DHEAS showed nonsignificant positive association with ICC. Progesterone was uninfluential. Among postmenopausal women, associations with ICC were found for T (OR = 3.14; 95% CI, 1.21-9.37), whereas E(2) and fT showed nonsignificant positive association. SHBG level was unrelated to ICC risk in postmenopausal women. No associations between any hormone and CIN3 were detected in either pre- or postmenopausal women. CONCLUSIONS: Our findings suggest for the first time that T and possibly E(2) may be involved in the etiology of ICC. IMPACT: The responsiveness of cervical tumors to hormone modulators is worth exploring.

Menopausal hormone therapy and risk of ovarian cancer in the European prospective investigation into cancer and nutrition.

The association between menopausal hormone therapy (HT) and risk of ovarian cancer was assessed among 126,920 post-menopausal women recruited into the European Prospective Investigation into Cancer and Nutrition. After an average of 9-year follow-up, 424 incident ovarian cancers were diagnosed. Cox models adjusted for body mass index, smoking status, unilateral ovariectomy, simple hysterectomy, age at menarche, number of full-term pregnancies, and duration of oral contraceptives were used. Compared with baseline never use, current use of any HT was positively associated with risk (HR [hazard ratio], 1.29; 95% CI [confidence interval], 1.01-1.65), while former use was not (HR, 0.96; 95% CI, 0.70-1.30). Current estrogen-only HT was associated with a 63% higher risk (HR, 1.63; 95% CI, 1.08-2.47), while current estrogen plus progestin was associated with a smaller and non-significant higher risk (HR, 1.20; 95% CI, 0.89-1.62). Use of tibolone was associated with a twofold greater risk (HR, 2.19; 95% CI, 1.06-4.50), but was based on small numbers. In conclusion, women who currently use HT have a moderate increased risk of ovarian cancer, and which may be stronger for estrogen-only than estrogen plus progestin preparations.