Heterogeneity of Associations between Total and Types of Fish Intake and the Incidence of Type 2 Diabetes: Federated Meta-Analysis of 28 Prospective Studies Including 956,122 Participants.

The association between fish consumption and new-onset type 2 diabetes is inconsistent and differs according to geographical location. We examined the association between the total and types of fish consumption and type 2 diabetes using individual participant data from 28 prospective cohort studies from the Americas (6), Europe (15), the Western Pacific (6), and the Eastern Mediterranean (1) comprising 956,122 participants and 48,084 cases of incident type 2 diabetes. Incidence rate ratios (IRRs) for associations of total fish, shellfish, fatty, lean, fried, freshwater, and saltwater fish intake and type 2 diabetes were derived for each study, adjusting for a consistent set of confounders and combined across studies using random-effects meta-analysis. We stratified all analyses by sex due to observed interaction (p = 0.002) on the association between fish and type 2 diabetes. In women, for each 100 g/week higher intake the IRRs (95% CIs) of type 2 diabetes were 1.02 (1.01-1.03, I2 = 61%) for total fish, 1.04 (1.01-1.07, I2 = 46%) for fatty fish, and 1.02 (1.00-1.04, I2 = 33%) for lean fish. In men, all associations were null. In women, we observed variation by geographical location: IRRs for total fish were 1.03 (1.02-1.04, I2 = 0%) in the Americas and null in other regions. In conclusion, we found evidence of a neutral association between total fish intake and type 2 diabetes in men, but there was a modest positive association among women with heterogeneity across studies, which was partly explained by geographical location and types of fish intake. Future research should investigate the role of cooking methods, accompanying foods and environmental pollutants, but meanwhile, existing dietary regional, national, or international guidelines should continue to guide fish consumption within overall healthy dietary patterns.

Does sauna bathing protect against dementia?

Repeated heat exposure like sauna bathing is suggested to beneficially affect against dementia development. The epidemiological evidence is, however, scarce. Therefore, we studied the association between heat exposure during sauna bathing (i.e., the frequency of sauna bathing, frequency of heat sessions, length of stay in heat, sauna temperature) and the subsequent risk of dementia. A prospective cohort study was conducted based on 13,994 men and women aged 30-69 and free from dementia diagnosis from the Finnish Mobile Clinic Follow-up Survey. During a follow-up of 39 years, a total of 1805 dementia patients were diagnosed. The sauna bathing data was gathered from a questionnaire. Analyses based on the Cox model included the sauna bathing variables and the potential confounding factors. Sauna bathing frequency was related to a reduced risk of dementia after adjustment for the potential sociodemographic, lifestyle, and metabolic risk factors of dementia considered. The hazard ratio of dementia between individuals sauna bathing 9-12 times per month in comparison with those not sauna bathing or sauna bathing less than four times per month was 0.47 (95% CI = 0.25-0.88) during the first 20 years of follow-up and 0.81 (95% CI = 0.69-0.97) during the whole follow-up. The results are in line with the hypothesis that sauna bathing provides protection against dementia. Further studies are required to verify the suggested benefits of sauna bathing.

Serum 25-hydroxyvitamin d concentration and risk of dementia.

BACKGROUND: High vitamin D status has been hypothesized to protect against dementia. The aim of the current study was to investigate whether serum 25-hydroxyvitamin D (25(OH)D) level predicts dementia risk. METHODS: The study was based on the Mini-Finland Health Survey. The study population consisted of 5010 men and women, aged 40-79 years, and free of dementia at baseline. During a 17-year follow up, 151 incident cases of dementia (International Classification of Diseases, revision 8, code 290) occurred, according to population registers. Serum 25(OH)D concentration was determined from serum samples frozen at -20 °C and stored at baseline. RESULTS: Among women, these with higher serum 25(OH)D concentrations showed a reduced risk of dementia. The hazard ratio between the highest and lowest quartiles of serum 25(OH)D was 0.33 (95% confidence interval = 0.15-0.73) in women and 0.74 (0.29-1.88) in men, after adjustment for age, month of blood draw, education, marital status, physical activity, smoking, alcohol consumption, body mass index, blood pressure, plasma fasting glucose, serum triglycerides, and serum total cholesterol. CONCLUSIONS: The results are in line with the hypothesis that low vitamin D status may be a risk factor for dementia.

Vitamin D status is associated with sociodemographic factors, lifestyle and metabolic health.

PURPOSE: Low serum 25(OH)D concentration has been shown to predict the occurrence of several chronic diseases. It is, however, still unclear whether the associations are causal or due to confounding. The aim of this study was to investigate the associations between serum 25(OH)D concentration and sociodemographic, lifestyle and metabolic health-related factors. METHODS: The study population comprised 5,714 men and women, aged 30-79 years, from the Health 2000 Survey representing the Finnish population. Serum 25(OH)D concentration was determined by radioimmunoassay from serum samples frozen at -70 °C. Sociodemographic, lifestyle and metabolic factors were determined by questionnaires, interviews and measurements. Linear regression was used to assess the associations between serum 25(OH)D and the factors studied. RESULTS: The mean serum 25(OH)D concentration was 45.3 nmol/l and it varied between categories of sociodemographic, lifestyle and metabolic health variables. Older age, being married or cohabiting and higher education were related to higher serum 25(OH)D concentration. Those with the healthiest lifestyle estimated by a lifestyle index based on body mass index, physical activity, smoking, alcohol consumption and diet had 15.8 nmol/l higher serum 25(OH)D concentration compared to those with the unhealthiest lifestyle. Of the indicators of metabolic health, only waist circumference and HDL cholesterol were significantly associated with 25(OH)D after adjustment for sociodemographic, lifestyle and other metabolic health factors. CONCLUSION: This study suggests that serum 25(OH)D concentration is associated with a multitude of sociodemographic, lifestyle and metabolic health factors. Thus, it is possible that such factors confound associations observed between serum 25(OH)D concentration and chronic diseases.

Alcohol consumption and bone mineral density in elderly women.

OBJECTIVE: Findings regarding alcohol consumption and bone mineral density (BMD) in elderly women have been inconsistent. The objective of the present study was to explore the association of alcohol intake with BMD in elderly women. DESIGN: This cohort study included women from the population-based Kuopio Osteoporosis Risk Factor and Prevention - Fracture Prevention Study (OSTPRE-FPS). Alcohol intake and potential confounders were assessed at baseline and after 3 years of follow-up using a lifestyle questionnaire. In addition, an FFQ was distributed in the third year to measure dietary intake, including alcohol. Women underwent BMD measurements at the femoral neck and lumbar spine at baseline and after 3 years of follow-up. SETTING: Kuopio Province, Finland. SUBJECTS: Three hundred elderly women (mean age 67·8 years) who provided both BMD measurements and FFQ data. RESULTS: Alcohol consumption estimated from the FFQ and lifestyle questionnaire was significantly associated with BMD at both measurement sites after adjustment for potential confounders, including lifestyle and dietary factors (P < 0·05). Using the FFQ, women drinking >3 alcoholic drinks/week had significantly higher BMD than abstainers, 12·0 % at the femoral neck and 9·2 % at the lumbar spine. Results based on the lifestyle questionnaire showed higher BMD values for all alcohol-consuming women at the femoral neck and for women drinking 1-3 alcoholic beverages/week at the lumbar spine, compared with non-users. CONCLUSIONS: The results from OSTPRE-FPS suggest that low to moderate alcohol intake may exert protective effects on bone health in elderly women.

Validation of a semi-quantitative FFQ using food records as a reference in older women in the Kuopio Fracture Prevention Study (OSTPRE-FPS).

OBJECTIVE: To validate an eighty-nine-item semi-quantitative FFQ for measurement of nutrient intakes in elderly women. DESIGN: FFQ and 3 d food records were filled in by women participating in the Kuopio Fracture Prevention Study (OSTPRE-FPS). Data on intakes of energy, fat, protein, carbohydrate, fibre, Ca, Fe, P, K, Mg, folic acid, vitamin B12, vitamin C, vitamin D and vitamin K from ninety-nine women were available to assess the agreement of the two methods. Validity was assessed using correlation coefficients, cross-classification into quintile categories and Bland-Altman plots. Nutrients relevant to bone health were assessed. SETTING: OSTPRE-FPS in Finland. SUBJECTS: Elderly women with a mean age 71·3 years. RESULTS: The FFQ overestimated energy and nutrient intakes as compared with food records by 30-50%. The highest correlation coefficients of the energy-adjusted nutrient intakes between the methods were observed for fibre (0·60), Mg (0·56) and folic acid (0·49) and the lowest for protein and vitamin D (both 0·19). The cross-classification of energy-adjusted nutrient intakes showed that on average 68% of the participants (range 62-78%) were classified into the same or an adjacent quintile category. CONCLUSIONS: The validity of energy and nutrient intakes measured with the FFQ was moderate as compared with 3 d food records in elderly women. The FFQ is a useful tool for the nutrient assessment of elderly women in epidemiological research.

Plant foods and the risk of cerebrovascular diseases: a potential protection of fruit consumption.

Studies on the association between plant foods and cerebrovascular diseases have given contradictory results suggesting the existence of some effect-modifying factors. The present study determines whether the consumption of plant foods (i.e. fruits and berries, vegetables, and cereals) predicts a decreased cerebrovascular disease incidence in a population with low fruit and vegetable and high wholegrain intake. This cohort study on 3932 men and women was based on data from the Finnish Mobile Clinic Health Examination Survey, conducted in 1968-72. The participants were 40-74 years of age and free of cardiovascular diseases at baseline. Data on the plant food consumption were derived from a 1-year dietary history interview. During a 24-year follow-up 625 cases of cerebrovascular diseases occurred, leading to either hospitalisation or death. An inverse association was found between fruit consumption and the incidence of cerebrovascular diseases, ischaemic stroke and intracerebral haemorrhage. The adjusted relative risks (RR) between the highest and lowest quartiles of intake of any cerebrovascular disease, ischaemic stroke and intracerebral haemorrhage were 0.75 (95 % CI 0.59, 0.94), 0.73 (95 % CI 0.54, 1.00) and 0.47 (95 % CI 0.24, 0.92), respectively. These associations were primarily due to the consumption of citrus fruits and occurred only in men. Total consumption of vegetables or cereals was not associated with the cerebrovascular disease incidence. The consumption of cruciferous vegetables, however, predicted a reduced risk of cerebrovascular diseases (RR 0.79; 95 % CI 0.63, 0.99), ischaemic stroke (RR 0.67; 95 % CI 0.49, 0.92) and intracerebral haemorrhage (RR 0.49; 95 % CI 0.25, 0.98). In conclusion, the consumption of fruits, especially citrus, and cruciferous vegetables may protect against cerebrovascular diseases.

Fish consumption and the incidence of cerebrovascular disease.

Studies of the beneficial role of fish consumption in the prevention of CVD are not consistent in their findings, particularly those studies that focus on the risk of stroke. The aim of the present study is to investigate the relationship between the consumption of different types of fish and the subsequent incidence of cerebrovascular disease (CVA). We prospectively evaluated the association between consumption of different types of fish and CVA in 3958 men and women aged 40-79 years who were free of heart disease and had participated in a health examination survey from 1967 to 1972. A total of 659 incident cases of CVA occurred during a follow-up until the end of 1994. A dietary history interview method provided data on habitual consumption of fish and other foods over the preceding year at baseline. Total fish intake did not predict CVA, but consumption of salted fish suggested an increased risk of intracerebral haemorrhage. The relative risk of intracerebral haemorrhage between the highest tertile of salted fish consumption and non-consumers was 1.98 (95 % CI 1.02, 3.84; P for trend = 0.06) after adjustment for age, sex, energy intake, smoking, BMI, physical activity, geographic area, occupation, diabetes, use of post-menopausal hormones, serum cholesterol, hypertension, and consumptions of butter, vegetables, fruits and berries. The relationship between fish consumption and stroke risk is not straightforward. How the fish is prepared for consumption may play an important role, affecting the association.

Consumption of sweetened beverages and intakes of fructose and glucose predict type 2 diabetes occurrence.

The role of intakes of different sugars in the development of type 2 diabetes was studied in a cohort of 4,304 men and women aged 40-60 y and initially free of diabetes at baseline in 1967-1972. Food consumption data were collected using a dietary history interview covering the habitual diet during the previous year. The intakes of different sugars were calculated and divided in quartiles. During a 12-y follow-up, 177 incidents of type 2 diabetes cases were identified from a nationwide register. Combined intake of fructose and glucose was associated with the risk of type 2 diabetes but no significant association was observed for intakes of sucrose, lactose, or maltose. The relative risk between the highest and lowest quartiles of combined fructose and glucose intake was 1.87 (95% [CI] = 1.19, 2.93; P = 0.003). The corresponding relative risks between the extreme quartiles of consumption of food items contributing to sugar intakes were 1.69 (95% [CI] = 1.17, 2.43; P < 0.001) for sweetened berry juice and 1.67 (95% [CI] = 0.98, 2.87; P = 0.01) for soft drinks. Our findings support the view that higher intake of fructose and glucose and sweetened beverages may increase type 2 diabetes risk.

Intake of fish and long-chain n-3 fatty acids and the risk of coronary heart mortality in men and women.

This prospective study investigated the relationship between the consumption of fish and intake of long-chain n-3 fatty acids and the risk of coronary heart mortality in 2775 men and 2445 women aged from 30 to 79 years who were free of CHD and had participated in a health examination survey from 1967 to 1972. In total, 335 men and 163 women died of CHD during a follow-up until the end of 1992. A dietary history interview method provided data on habitual consumption of fish and other foods over the preceding year at baseline. The intakes of long-chain n-3 fatty acids were calculated on the basis of food composition values of Finnish foods. Higher consumption of fish was associated with a decreased risk of CHD among women, whereas no significant association was seen among men. The relative risk between the highest and the lowest quintile for fish consumption was 1.00 (95 % CI 0.70, 1.43; P for trend 0.83) for men and 0.59 (95 % CI 0.36, 0.99; P for trend 0.02) for women in analysis adjusting for age, energy intake, geographical area, BMI, serum cholesterol, blood pressure, smoking, occupation and diabetes; however, after adjustment for dietary confounders this association was no longer significant. The intake of n-3 fatty acids was not significantly associated with the risk of CHD in either men or women. In conclusion, our results for women are in line with the suggested protective effect of fish consumption against CHD but a similar association was not, however, found in men.

Dietary patterns and the incidence of type 2 diabetes.

Major dietary patterns were studied for the ability to predict type 2 diabetes mellitus in a cohort of 4,304 Finnish men and women aged 40-69 years and free of diabetes at baseline in 1967-1972. Factor analysis was used to identify dietary patterns from dietary data that were collected using a 1-year dietary history interview. A total of 383 incident cases of type 2 diabetes occurred during a 23-year follow-up. Two major dietary patterns were identified. The pattern labeled "prudent" was characterized by higher consumption of fruits and vegetables, and the pattern labeled "conservative" was characterized by consumption of butter, potatoes, and whole milk. The relative risks (adjusted for nondietary confounders) between the extreme quartiles of the pattern scores were 0.72 (95% confidence interval: 0.53, 0.97; p(trend) = 0.03) for the prudent pattern and 1.49 (95% confidence interval: 1.11, 2.00; p(trend) = 0.01) for the conservative pattern. Thus, the prudent dietary pattern score was associated with a reduced risk and the conservative pattern score was associated with an increased risk of type 2 diabetes. In light of these results, it appears conceivable that the risk of developing type 2 diabetes can be reduced by changing dietary patterns.

Dietary antioxidant intake and risk of type 2 diabetes.

OBJECTIVE: The intake of antioxidants was studied for its ability to predict type 2 diabetes. RESEARCH DESIGN AND METHODS: A cohort of 2,285 men and 2,019 women 40-69 years of age and free of diabetes at baseline (1967-1972) was studied. Food consumption during the previous year was estimated using a dietary history interview. The intake of vitamin C, four tocopherols, four tocotrienols, and six carotenoids was calculated. During a 23-year follow-up, a total of 164 male and 219 female incident cases occurred. RESULTS: Vitamin E intake was significantly associated with a reduced risk of type 2 diabetes. The relative risk (RR) of type 2 diabetes between the extreme quartiles of the intake was 0.69 (95% CI 0.51-0.94, P for trend = 0.003). Intakes of alpha-tocopherol, gamma-tocopherol, delta-tocopherol, and beta-tocotrienol were inversely related to a risk of type 2 diabetes. Among single carotenoids, beta-cryptoxanthin intake was significantly associated with a reduced risk of type 2 diabetes (RR 0.58, 95% CI 0.44-0.78, P < 0.001). No association was evident between intake of vitamin C and type 2 diabetes risk. CONCLUSIONS: This study supports the hypothesis that development of type 2 diabetes may be reduced by the intake of antioxidants in the diet.

Serum fatty acids and breast cancer incidence.

Fatty acid composition of the diet may be essential to the development of breast cancer. We studied the ability of several fatty acids of serum total lipids to predict breast cancer incidence in a case-control study nested within a longitudinal population study. The proportions of fatty acids in serum total lipids were determined from stored serum samples collected at baseline for 127 incident breast cancer cases and 242 matched controls. Women with a higher proportion of total polyunsaturated fatty acids (PUFAs) in serum had a reduced risk of breast cancer. The odds ratio (OR) between the highest and lowest tertiles of serum PUFA was 0.31 (95% confidence interval, CI = 0.12-0.77). This association was mainly due to n-6 PUFAs and especially to linoleic acid. The ORs were 0.35 (CI = 0.14-0.84) and 0.29 (CI = 0.12-0.73), respectively. Of the monounsaturated fatty acids (MUFAs), higher trans-11-18:1 levels were related to an increased breast cancer risk (OR = 3.69, CI = 1.35-10.06). The association was stronger in postmenopausal than in premenopausal women. The present study suggests that higher serum proportions of the n-6 PUFA linoleic acid and lower proportions of the MUFA trans-11-18:1 fatty acid predict a reduced incidence of breast cancer.

Whole-grain and fiber intake and the incidence of type 2 diabetes.

BACKGROUND: Epidemiologic evidence of a preventive effect of whole grain against type 2 diabetes is mainly based on data from women. Information specific to men and women is needed. OBJECTIVE: The objective was to study the relation between the intake of whole grain and fiber and the subsequent incidence of type 2 diabetes. DESIGN: The design was a cohort study of 2286 men and 2030 women aged 40-69 y and initially free of diabetes. Food consumption data were collected from 1966 through 1972 with the use of a dietary history interview covering the habitual diet during the previous year. During a 10-y follow-up, incident type 2 diabetes cases were identified in 54 men and 102 women from a nationwide register. RESULTS: Whole-grain consumption was associated with a reduced risk of type 2 diabetes. The relative risk (adjusted for age, sex, geographic area, smoking status, body mass index, energy intake, and intakes of vegetables, fruit, and berries) between the highest and lowest quartiles of whole-grain consumption was 0.65 (95% CI: 0.36, 1.18; P for trend = 0.02). Cereal fiber intake was also associated with a reduced risk of type 2 diabetes. The relative risk between the extreme quartiles of cereal fiber intake was 0.39 (95% CI: 0.20, 0.77; P = 0.01). CONCLUSIONS: An inverse association between whole-grain intake and the risk of type 2 diabetes was found. The similar result for cereal fiber intake suggests that the whole-grain association is due to cereal fiber or another factor related to cereal fiber intake.

Flavonoid intake and risk of chronic diseases.

BACKGROUND: Flavonoids are effective antioxidants and may protect against several chronic diseases. OBJECTIVE: The association between flavonoid intake and risk of several chronic diseases was studied. DESIGN: The total dietary intakes of 10 054 men and women during the year preceding the baseline examination were determined with a dietary history method. Flavonoid intakes were estimated, mainly on the basis of the flavonoid concentrations in Finnish foods. The incident cases of the diseases considered were identified from different national public health registers. RESULTS: Persons with higher quercetin intakes had lower mortality from ischemic heart disease. The relative risk (RR) between the highest and lowest quartiles was 0.79 (95% CI: 0.63, 0.99: P for trend = 0.02). The incidence of cerebrovascular disease was lower at higher kaempferol (0.70; 0.56, 0.86; P = 0.003), naringenin (0.79; 0.64, 0.98; P = 0.06), and hesperetin (0.80; 0.64, 0.99; P = 0.008) intakes. Men with higher quercetin intakes had a lower lung cancer incidence (0.42; 0.25, 0.72; P = 0.001), and men with higher myricetin intakes had a lower prostate cancer risk (0.43; 0.22, 0.86; P = 0.002). Asthma incidence was lower at higher quercetin (0.76; 0.56, 1.01; P = 0.005), naringenin (0.69; 0.50, 0.94; P = 0.06), and hesperetin (0.64; 0.46, 0.88; P = 0.03) intakes. A trend toward a reduction in risk of type 2 diabetes was associated with higher quercetin (0.81; 0.64, 1.02; P = 0.07) and myricetin (0.79; 0.62, 1.00; P = 0.07) intakes. CONCLUSION: The risk of some chronic diseases may be lower at higher dietary flavonoid intakes.