Milk intake and hip fracture incidence in community-dwelling old Icelandic adults.

Milk and milk products have been known as important for bone health. Can ingestion of milk and milk products lower hip fracture risk for older adults? In this study, older Icelandic adults who were ingesting higher milk had a lower risk of hip fractures. INTRODUCTION: This study describes associations between milk intake and hip fracture risk in older Icelanders. The data indicate that no/low milk consumption is related to greater hip fracture risk. Hip fracture can have a severe effect on the life of older adults. Health authorities recommend milk intake for better bone health. However, previous studies addressing this association have been divergent. METHODS: This prospective study included 4614 subjects (mean age 76 years) recruited between 2002 and 2006 into the Age, Gene/Environment Susceptibility-Reykjavik (AGES-Reykjavik) study. Information on hip fractures occurring between recruitment and end of follow-up in 2012 was extracted from hospital records. RESULTS: A total of 14% of participants reported milk intake < 0.5 times/day (the lowest category) and 22% of the participants consumed at least milk two times/day (highest category). Milk consumption was positively related to the volumetric bone mineral density at baseline with a sex- and age-adjusted difference of 8.95 ± 2.5 mg/cm3 between the highest compared to lowest milk intake categories (P < 0.001). During the follow-up, 7.4% of participants had a hip fracture, and we observed a decreased risk of incident hip fractures in the highest compared to the lowest milk intake category with a hazard ratio of 0.69 (95% CI: 0.47-0.99) in adjusted model. Further analysis indicated a linear relationship between milk intake and fracture risk (P-value for linear trend < 0.001). CONCLUSION: Milk intake is associated with a lower risk of incident hip fracture in a linear way in Icelandic community-dwelling older adults.

Growth Rate in Childhood and Adolescence and the Risk of Breast and Prostate Cancer: A Population-Based Study.

Growth rate is regulated by hormonal pathways that might affect early cancer development. We explored the association between rate of growth in height from ages 8 to 13 years (childhood) and from age 13 to attainment of adult height (adolescence), as measured at study entry, and the risk of breast or prostate cancer. Participants were 2,037 Icelanders born during 1915-1935, who took part in the Reykjavik Study, established in 1967. Height measurements were obtained from school records and at study entry. We used multivariable Cox regression models to calculate hazard ratios with 95% confidence intervals of breast and prostate cancer by rates of growth in tertiles. During a mean follow-up of 66 years (women) and 64 years (men), 117 women were diagnosed with breast cancer and 118 men with prostate cancer (45 with advanced disease). Women in the highest growth-rate tertile in adolescence had a higher risk of breast cancer (hazard ratio = 2.4, 95% confidence interval: 1.3, 4.3) compared with women in the lowest tertile. A suggestive inverse association was observed for highest adolescent growth rate in men and advanced prostate cancer: hazard ratio = 0.4, 95% confidence interval: 0.2, 1.0. Rapid growth, particularly in adolescence may affect cancer risk later in life.

Dietary patterns in adolescence and risk of colorectal cancer: a population-based study.

PURPOSE: To study whether dietary patterns in adolescence are associated with risk of colorectal cancer (CRC). METHODS: Food frequency data were obtained from the AGES-Reykjavik study, conducted between 2002 and 2006, which included 5,078 (58% women) participants with mean age of 77 (± 5.8) years. Principal component analysis was used to identify dietary patterns. Participants were followed through linkage to the Icelandic Cancer Registry. Multivariable Cox models were used to calculate hazard ratios (HR) of CRC and 95% confidence interval (CI) by dietary patterns. RESULTS: During the follow-up period (mean 8.2 years), 136 participants (75 women and 61 men) were diagnosed with CRC. The main dietary pattern in adolescence was characterized by high intake of traditional food items consumed in the earlier half of the twentieth century, namely, salted or smoked meat and fish, milk, offal, rye bread, and oatmeal. Compared to the lowest tertile, the middle tertile of this pattern was associated with increased risk of CRC (HR 1.63, 95% CI 1.04-2.57), while the highest tertile was not statistically associated with CRC (HR 1.48, 95% CI 0.93-2.37), except among women (HR 2.06, 95% CI 1.11-3.84). CONCLUSION: These data suggest that strong adherence to a traditional Icelandic diet in adolescence might increase the risk of CRC, particularly among women. More research is need on the association between food items and dietary patterns of relevance to CRC at different points in the life cycle.

Pre-diagnostic 25-hydroxyvitamin D levels and survival in cancer patients.

PURPOSE: Our main aim was to explore whether pre-diagnostic circulating levels of 25-hydroxyvitamin D (25(OH)D) among older individuals with cancer were associated with overall and cancer-specific survival after diagnosis. DESIGN: We used data from the Reykjavik-AGES Study on participants (n = 4,619) without cancer at entry, when blood samples were taken for 25(OH)D standardized measurements. The association with cancer risk, all-cause- and cancer-specific mortality was assessed among those later diagnosed with cancer, comparing four 25(OH)D categories, using 50-69.9 nmol/L as the reference category. RESULTS: Cancer was diagnosed in 919 participants on average 8.3 years after blood draw. No association was observed between the reference group and other 25(OH)D groups and total cancer incidence. Mean age at diagnosis was 80.9 (± 5.7) years. Of those diagnosed, 552 died during follow-up, 67% from cancer. Low pre-diagnostic levels of 25(OH)D < 30 nmol/L were significantly associated with increased total mortality (HR: 1.39, 95% CI 1.03, 1.88) and non-significantly with cancer-specific mortality (HR: 1.33, 95% CI 0.93, 1.90). Among patients surviving more than 2 years after diagnosis, higher pre-diagnostic 25(OH)D levels (≥ 70 nmol/L) were associated with lower risk of overall (HR: 0.68, 95% CI 0.46, 0.99) and cancer-specific mortality (HR: 0.47, 95% CI 0.26, 0.99). CONCLUSIONS: Among elderly cancer patients, low pre-diagnostic serum 25(OH)D levels (< 30 nmol/L) were associated with increased overall mortality.

Midlife metabolic factors and prostate cancer risk in later life.

Metabolic syndrome is associated with several cancers, but evidence for aggressive prostate cancer is sparse. We prospectively investigated the influence of metabolic syndrome and its components on risk of total prostate cancer and measures of aggressive disease in a cohort of Icelandic men. Men in the Reykjavik Study (n = 9,097, enrolled 1967-1987) were followed for incident (n = 1,084 total; n = 378 advanced; n = 148 high-grade) and fatal (n = 340) prostate cancer until 2014. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for (1) measured metabolic factors at cohort entry (body mass index (BMI), blood pressure, triglycerides, fasting blood glucose) and (2) a metabolic syndrome score (range 0-4) combining the risk factors: BMI ≥30 kg/m2 ; systolic blood pressure (SBP) ≥130 or diastolic blood pressure (DBP) ≥85 mm Hg or taking antihypertensives; triglycerides ≥150 mg/dl; fasting blood glucose ≥100 mg/dl or self-reported type 2 diabetes. Hypertension and type 2 diabetes were associated with a higher risk of total, advanced, high-grade, and fatal prostate cancer, independent of BMI. Neither BMI nor triglycerides were associated with prostate cancer risk. Higher metabolic syndrome score (3-4 vs 0) was associated with a higher risk of fatal prostate cancer (HR 1.55; 95% CI: 0.89, 2.69; p trend = 0.08), although this finding was not statistically significant. Our findings suggest a positive association between midlife hypertension and diabetes and risk of total and aggressive prostate cancer. Further, metabolic syndrome as a combination of factors was associated with an increased risk of fatal prostate cancer.

Fish and fish-liver oil consumption in adolescence and midlife and risk of CHD in older women.

OBJECTIVE: To study the association of fish and fish-liver oil consumption across the lifespan with CHD later in life among Icelandic women, with special emphasis on the effects of consumption in adolescence. DESIGN: Prevalence association study. Logistic regression was used to estimate odds ratios and 95 % confidence intervals of CHD according to fish or fish-liver oil exposure. Models were adjusted for age, education, concurrent diet and other known risk factors. SETTING: The study was nested within the AGES-Reykjavik Study, conducted in Reykjavik, Iceland. SUBJECTS: Participants were 3326 women aged 66-96 years, with available information on CHD status at entry to the study and information on fish and fish-liver oil consumption during midlife and adolescence. Dietary habits were assessed retrospectively using a validated FFQ. RESULTS: CHD was identified in 234 (7·9 %) women. Compared with women with no intake of fish-liver oil in adolescence or midlife, women who consumed fish-liver oil at least three times weekly in adolescence or in midlife had a decreased risk of CHD (OR=0·62; 95 % CI 0·45, 0·85 and OR=0·68; 95 % CI 0·50, 0·94, respectively). No associations were observed between fish intake (>2 portions/week v. ≤2 portions/week) in adolescence or midlife and CHD in this population with high fish intake. CONCLUSIONS: Fish-liver oil consumption, from early life, may reduce the risk of CHD in older women. Lifelong nutrition may be of importance in the prevention of CHD in older women.

Cod liver oil consumption at different periods of life and bone mineral density in old age.

Cod liver oil is a traditional source of vitamin D in Iceland, and regular intake is recommended partly for the sake of bone health. However, the association between lifelong consumption of cod liver oil and bone mineral density (BMD) in old age is unclear. The present study attempted to assess the associations between intake of cod liver oil in adolescence, midlife, and old age, and hip BMD in old age, as well as associations between cod liver oil intake in old age and serum 25-hydroxyvitamin D (25(OH)D) concentration. Participants of the Age, Gene/Environment Susceptibility-Reykjavik Study (age 66-96 years; n 4798), reported retrospectively cod liver oil intake during adolescence and midlife, as well as the one now in old age, using a validated FFQ. BMD of femoral neck and trochanteric region was measured by volumetric quantitative computed tomography, and serum 25(OH)D concentration was measured by means of a direct, competitive chemiluminescence immunoassay. Associations were assessed using linear regression models. No significant association was seen between retrospective cod liver oil intake and hip BMD in old age. Current intake of aged men was also not associated with hip BMD, while aged women with daily intakes had z-scores on average 0.1 higher, compared with those with an intake of < once/week. Although significant, this difference is small, and its clinical relevance is questionable. Intake of aged participants was positively associated with serum 25(OH)D: individuals with intakes of < once/week, one to six time(s)/week and daily intake had concentrations of approximately 40, 50 and 60 nmol/l respectively (P for trend < 0.001).

Iodine status of pregnant women in a population changing from high to lower fish and milk consumption.

OBJECTIVES: Pregnancy is one of the most critical periods for iodine deficiency. The aim of the present study was to assess the iodine status and dietary intake of pregnant women in a population changing from high to lower consumption of milk and fish. DESIGN: Cross-sectional observational study. Urine samples were collected for measuring urinary iodine concentration (UIC) and creatinine, and blood samples for measuring serum thyroid-stimulating hormone (TSH). Frequency of consumption of selected food and beverages was obtained through a semi-quantitative validated FFQ. The difference in the distribution of UIC, ratio of iodine to creatinine (I:Cr) and TSH between groups following recommendations on fish and dairy product intake or not (fish ≥2 times/week as a main meal, diary products ≥2 portions/d) was assessed. SETTING: Primary Health Care of the Capital Area, Reykjavik, Iceland. SUBJECTS: Randomly selected pregnant women (19-43 years old, n 162). RESULTS: The median UIC was 180 µg/l, I:Cr 173 µg/g and TSH 1·5 mmol/l. Women who did not consume fish ≥2 times/week and also did not consume dairy products in line with the recommended intake level of ≥2 portions/d had median UIC of 160 µg/l (I:Cr 149 µg/g) compared with 220 µg/l (I:Cr 190 µg/g) in the group following both the recommendations for fish and those for dairy products. Use of dietary supplements in the two groups was similar. CONCLUSIONS: Iodine status in the population studied was within the optimal range (150-249 µg/d) defined by the WHO.

Milk intake in early life and risk of advanced prostate cancer.

The authors investigated whether early-life residency in certain areas of Iceland marked by distinct differences in milk intake was associated with risk of prostate cancer in a population-based cohort of 8,894 men born between 1907 and 1935. Through linkage to cancer and mortality registers, the men were followed for prostate cancer diagnosis and mortality from study entry (in waves from 1967 to 1987) through 2009. In 2002-2006, a subgroup of 2,268 participants reported their milk intake in early, mid-, and current life. During a mean follow-up period of 24.3 years, 1,123 men were diagnosed with prostate cancer, including 371 with advanced disease (stage 3 or higher or prostate cancer death). Compared with early-life residency in the capital area, rural residency in the first 20 years of life was marginally associated with increased risk of advanced prostate cancer (hazard ratio = 1.29, 95% confidence interval (CI): 0.97, 1.73), particularly among men born before 1920 (hazard ratio = 1.64, 95% CI: 1.06, 2.56). Daily milk consumption in adolescence (vs. less than daily), but not in midlife or currently, was associated with a 3.2-fold risk of advanced prostate cancer (95% CI: 1.25, 8.28). These data suggest that frequent milk intake in adolescence increases risk of advanced prostate cancer.

Rye bread consumption in early life and reduced risk of advanced prostate cancer.

OBJECTIVE: To determine whether consumption of whole-grain rye bread, oatmeal, and whole-wheat bread, during different periods of life, is associated with risk of prostate cancer (PCa). METHODS: From 2002 to 2006, 2,268 men, aged 67-96 years, reported their dietary habits in the AGES-Reykjavik cohort study. Dietary habits were assessed for early life, midlife, and current life using a validated food frequency questionnaire. Through linkage to cancer and mortality registers, we retrieved information on PCa diagnosis and mortality through 2009. We used regression models to estimate odds ratios (ORs) and hazard ratios (HRs) for PCa according to whole-grain consumption, adjusted for possible confounding factors including fish, fish liver oil, meat, and milk intake. RESULTS: Of the 2,268 men, 347 had or were diagnosed with PCa during follow-up, 63 with advanced disease (stage 3+ or died of PCa). Daily rye bread consumption in adolescence (vs. less than daily) was associated with a decreased risk of PCa diagnosis (OR = 0.76, 95 % confidence interval (CI): 0.59-0.98) and of advanced PCa (OR = 0.47, 95 % CI: 0.27-0.84). High intake of oatmeal in adolescence (≥5 vs. ≤4 times/week) was not significantly associated with risk of PCa diagnosis (OR = 0.99, 95 % CI: 0.77-1.27) nor advanced PCa (OR = 0.67, 95 % CI: 0.37-1.20). Midlife and late life consumption of rye bread, oatmeal, or whole-wheat bread was not associated with PCa risk. CONCLUSION: Our results suggest that rye bread consumption in adolescence may be associated with reduced risk of PCa, particularly advanced disease.

Assessing validity of a short food frequency questionnaire on present dietary intake of elderly Icelanders.

BACKGROUND: Few studies exist on the validity of food frequency questionnaires (FFQs) administered to elderly people. The aim of this study was to assess the validity of a short FFQ on present dietary intake, developed specially for the AGES-Reykjavik Study, which includes 5,764 elderly individuals. Assessing the validity of FFQs is essential before they are used in studies on diet-related disease risk and health outcomes. METHOD: 128 healthy elderly participants (74 y ± 5.7; 58.6% female) answered the AGES-FFQ, and subsequently filled out a 3-day weighed food record. Validity of the AGES-FFQ was assessed by comparing its answers to the dietary data obtained from the weighed food records, using Spearman's rank correlation, Chi-Square/Kendall's tau, and a Jonckheere-Terpstra test for trend. RESULT: For men a correlation ≥ 0.4 was found for potatoes, fresh fruits, oatmeal/muesli, cakes/cookies, candy, dairy products, milk, pure fruit juice, cod liver oil, coffee, tea and sugar in coffee/tea (r = 0.40-0.71). A lower, but acceptable, correlation was also found for raw vegetables (r = 0.33). The highest correlation for women was found for consumption of rye bread, oatmeal/muesli, raw vegetables, candy, dairy products, milk, pure fruit juice, cod liver oil, coffee and tea (r = 0.40-0.61). An acceptable correlation was also found for fish topping/salad, fresh fruit, blood/liver sausage, whole-wheat bread, and sugar in coffee/tea (r = 0.28-0.37). Questions on meat/fish meals, cooked vegetables and soft drinks did not show a significant correlation to the reference method. Pearson Chi-Square and Kendall's tau showed similar results, as did the Jonckheere-Terpstra trend test. CONCLUSION: A majority of the questions in the AGES-FFQ had an acceptable correlation and may be used to rank individuals according to their level of intake of several important foods/food groups. The AGES-FFQ on present diet may therefore be used to study the relationship between consumption of several specific foods/food groups and various health-related endpoints gathered in the AGES-Reykjavik Study.

Serum 25-Hydroxy-Vitamin D Status and Incident Hip Fractures in Elderly Adults: Looking Beyond Bone Mineral Density.

Observational studies have consistently reported a higher risk of fractures among those with low levels of serum 25-hydroxyvitamin D (25(OH)D). Emerging evidence suggests that low serum 25(OH)D levels may increase the rate of falls through impaired physical function. Examine to what extent baseline measures of volumetric bone mineral density (vBMD), absolute bone mineral content (BMC), and markers of physical function may explain incident hip fractures in older adults with different serum levels of 25(OH)D. A prospective study of 4309 subjects (≥66 years) recruited between 2002 and 2006 into the Age, Gene/Environment Susceptibility-Reykjavik (AGES-Reykjavik) study. Hip fractures occurring until the end of 2012 were extracted from hospital records. Prevalence of serum 25(OH)D deficiency (<30 nmol/L), inadequacy (30-<50 nmol/L), and sufficiency (≥50 nmol/L) was 6%, 23%, and 71% for males; and 11%, 28%, and 53% for females, respectively. Female participants had ~30% lower absolute BMC compared to males. Serum 25(OH)D concentrations were positively associated with vBMD and BMC of the femoral neck and markers of physical function, including leg strength and balance. Those who had deficient compared to sufficient status at baseline had a higher age-adjusted risk of incidence hipfractures with hazard ratios (HRs) of 3.1 (95% confidence interval [CI], 1.9-5.2) and 1.8 (95% CI, 1.3-2.5) among males and females, respectively. When adjusting for vBMD and measures of physical function, the association was attenuated and became nonsignificant for males (1.3; 95% CI, 0.6-2.5) but remained significant for females (1.7; 95% CI, 1.1-2.4). Deficient compared to sufficient serum 25(OH)D status was associated with a higher risk of incident hip fractures. This association was explained by poorer vBMD and physical function for males but to a lesser extent for females. Lower absolute BMC among females due to smaller bone volume may account for these sex-specific differences. © 2021 American Society for Bone and Mineral Research (ASBMR).

Docosahexaenoic acid in red blood cells of women of reproductive age is positively associated with oral contraceptive use and physical activity.

Optimal intake of the long-chain n-3 polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA) and proper balance between intake of n-6 PUFA and n-3 PUFA are important for human health. Considerable evidence exists to show that DHA has a marked benefit during pregnancy. Lifestyle factors can affect the biosynthesis of DHA from dietary precursors, incorporation into membranes and degradation. The purpose of this study was to investigate the PUFA composition of red blood cells (RBCs) from women (n=40) in reproductive age, and how it is affected by diet and other lifestyle factors. Of all the lifestyle factors tested oral contraceptive use and physical activity were the ones correlated with DHA in RBCs, after adjustment for DHA intake. The findings indicate that oral contraceptive use and physical activity have a positive impact on the DHA status, as assessed by RBC level, of women in reproductive age.

Red blood cell n-3 polyunsaturated fatty acids in first trimester of pregnancy are inversely associated with placental weight.

OBJECTIVE: To investigate pregnancy outcome in relation to red blood cell (RBC) level of long-chain n-3 polyunsaturated fatty acids (PUFA) in the first trimester of pregnancy and the influence of lifestyle factors on the RBC level of long-chain n-3 PUFA. DESIGN AND SETTING: Observational study in a community with traditional fish and cod liver oil consumption. POPULATION: Seventy-seven healthy pregnant women. METHODS: The PUFA composition of RBC was measured in the 11th to 15th week of pregnancy. The women answered food frequency and lifestyle questionnaires. Information on pregnancy outcome was collected from birth records. MAIN OUTCOME MEASURES: Placental weight, long-chain n-3 PUFA in diet and RBC, smoking. RESULTS: Of all the pregnancy outcome variables tested, placental weight was the only one associated with long-chain n-3 PUFA in RBC. Inverse association was found between the proportion of long-chain n-3 PUFA in RBC and placental weight, adjusted for birthweight (p=0.035). The proportion of long-chain n-3 PUFA in RBC was positively related to long-chain n-3 PUFA intake (p<0.001) and negatively related to smoking (p=0.011). CONCLUSION: The human fetus relies on maternal supply and placental delivery of long-chain n-3 PUFA for optimal development and function, particularly of the central nervous system. Given the importance of dietary n-3 PUFA during pregnancy, further studies are warranted to investigate the relationship between placental weight, maternal long-chain n-3 PUFA status and smoking.

Dietary habits in adolescence and midlife and risk of breast cancer in older women.

Recent studies indicate that lifestyle factors in early life affect breast cancer risk. We therefore explored the association of high consumption of meat, milk, and whole grain products in adolescence and midlife, on breast cancer risk. We used data from the population based AGES-Reykjavik cohort (2002-2006), where 3,326 women with a mean age of 77 years (SD 6.0) participated. For food items and principal component derived dietary patterns we used Cox proportional models to calculate multivariate hazard ratios (HR) with 95% confidence intervals (95% CI). During a mean follow-up of 8.8 years, 97 women were diagnosed with breast cancer. For both adolescence and midlife, daily consumption of rye bread was positively associated with breast cancer (HR 1.7, 95% CI 1.1-2.6 and HR 1.8, 95% CI 1.1-2.9, respectively). In contrast, persistent high consumption of oatmeal was negatively associated with breast cancer (0.4, 95% CI 0.2-0.9). No association was found for other food items or dietary patterns that included rye bread. High rye bread consumption in adolescence and midlife may increase risk of late-life breast cancer whilst persistent consumption of oatmeal may reduce the risk.

Correction: Dietary habits in adolescence and midlife and risk of breast cancer in older women.

[This corrects the article DOI: 10.1371/journal.pone.0198017.].

Dietary intake is associated with risk of multiple myeloma and its precursor disease.

The etiology of monoclonal gammopathy of undetermined significance (MGUS), the precursor state of multiple myeloma (MM), is mostly unknown and no studies have been conducted on the effect of diet on MGUS or progression from MGUS to MM. We aimed to explore the association between common foods and MGUS and progression to MM. Data from the population-based AGES Study (N = 5,764) were utilized. Food frequency questionnaire was used to assess dietary intake during adolescence, midlife, and late life. Serum protein electrophoresis and serum free light-chain assay was performed to identify MGUS (n = 300) and LC-MGUS cases (n = 275). We cross linked our data with the Icelandic Cancer Registry to find cases of MM in the study group. We found that intake of fruit at least three times per week during adolescence was associated with lower risk of MGUS when compared to lower fruit consumption (OR = 0.62, 95% CI 0.41-0.95). We additionally found that intake of fruit at least three times per week during the late life period was associated with decreased risk of progressing from MGUS to MM (HR = 0.34, 95% CI 0.13-0.89) when compared to lower intake. Adolescent intake of fruit may reduce risk of MGUS, whereas fruit intake after MGUS onset may reduce risk of progressing to MM. Our findings suggest that diet might alter the risk of developing MGUS and progression to MM.

[Dietary intake of young Icelanders with psychotic disorders and weight development over an 8-12 months period].

INTRODUCTION: The prevalence of lifestyle related diseases is higher among people with psychotic disorders than the general population. The aim was to assess dietary intake of young people with psychotic disorders for the first time in Iceland. MATERIAL AND METHODS: Subjects were young people (n=48, age 18-30y) with psychotic disorders. Dietary intake was assessed by a 24-hour recall in July-August 2016, and compared with official recommendations and intake of the general public (n=250, age 18-30y). Body weight in the past eight to 12 months, was retrieved from medical records. RESULTS: Consumption of fruits, fish, dairy products, vegetable and fish oil was significantly lower among subjects when compared with the general public, while their soft drink and sweets consumption was higher (p<0.001). Furthermore, the contribution of added sugar was higher (15E% vs. 12E%) and protein intake lower (16E% vs. 18E%). Consumption of omega-3 fatty acids and vitamin D was lower among subjects than the general public and lower than recommended (0.04±0.3% omega-3 of total energy vs. 1.2±0.6%, p<0.001 and 3.1±4.2 µg vitamin D/day vs. 5.6±6.5 µg/day, p<0.001). Almost 40% of the subjects had gained >5% of their initial body weight in the past 8-2 months. CONCLUSION: Diet of young people with psychotic disorders is not consistent with recommendations and is worse than the diet of their peers in the general population. It is important to find ways to improve the diet and thereby nutrient intake of the group. Key words: psychotic disorders, schizophrenia, recommended dietary allowances, fatty acids, omega-3, vitamin D. Correspondence: Ingibjorg Gunnarsdottir, ingigun@landspitali.is.

Early Life Residence, Fish Consumption, and Risk of Breast Cancer.

Background: Little is known about fish intake throughout the life course and the risk of breast cancer.Methods: We used data on the first residence of 9,340 women born 1908 to 1935 in the Reykjavik Study as well as food frequency data for different periods of life from a subgroup of the cohort entering the Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study (n = 2,882).Results: During a mean follow-up of 27.3 years, 744 women were diagnosed with breast cancer in the Reykjavik Study. An inverse association of breast cancer was observed among women who lived through the puberty period in coastal villages, compared with women residing in the capital area [HR, 0.78; 95% confidence interval (CI), 0.61-0.99]. In the subgroup analysis of this Icelandic population, generally characterized by high fish intake, we found an indication of lower risk of breast cancer among women with high fish consumption (more than 4 portions per week) in adolescence (HR, 0.71; 95% CI, 0.44-1.13) and midlife (HR, 0.46; 95% CI, 0.22-0.97), compared with low consumers (2 portions per week or less). No association was found for fish liver oil consumption in any time period, which could be due to lack of a reference group with low omega-3 fatty acids intake in the study group.Conclusions: Our findings suggest that very high fish consumption in early to midlife may be associated with a reduced risk of breast cancer.Impact: Very high fish consumption in early adulthood to midlife may be associated with decreased risk of breast cancer. Cancer Epidemiol Biomarkers Prev; 26(3); 346-54. ©2016 AACR.