Dietary magnesium intake, serum high sensitivity C-reactive protein and the risk of incident knee osteoarthritis leading to hospitalization-A cohort study of 4,953 Finns.

OBJECTIVES: To study whether low dietary magnesium (Mg) intake and serum high sensitivity C-reactive protein (hs-CRP) predict the development of clinical knee osteoarthritis (OA). METHODS: The cohort consisted of 4,953 participants of a national health examination survey who were free of knee and hip OA at baseline. Information on the incidence of knee OA leading to hospitalization was drawn from the National Care Register for Health Care. During the follow-up of 10 years, 123 participants developed incident knee OA. Dietary magnesium intake was assessed on the basis of a food frequency questionnaire from the preceding year. We used Cox's proportional hazards model to estimate the strength of the association between the tertiles of dietary Mg intake and incident knee OA, adjusted for baseline age, gender, energy intake, BMI, history of physical workload, leisure time physical activity, injuries, knee complaints, the use of Mg supplements, and serum hs-CRP levels. RESULTS: At baseline, dietary Mg intake was inversely associated with serum hs-CRP even after adjustment for all the potential confounding factors. During the follow-up, the adjusted hazard ratios (with their 95% confidence intervals) for incident knee OA in dietary Mg intake tertiles were 1.00, 1.28 (0.78-2.10), and 1.38 (0.73-2.62); the p value for trend was 0.31. Serum hs-CRP level at baseline did not predict incident knee OA. CONCLUSIONS: The results do not support the hypothesis that low dietary Mg intake contributes to the development of clinical knee OA, although Mg intake is inversely associated with serum hs-CRP level.

Selenium and Prostate Cancer: Analysis of Individual Participant Data From Fifteen Prospective Studies.

BACKGROUND: Some observational studies suggest that a higher selenium status is associated with a lower risk of prostate cancer but have been generally too small to provide precise estimates of associations, particularly by disease stage and grade. METHODS: Collaborating investigators from 15 prospective studies provided individual-participant records (from predominantly men of white European ancestry) on blood or toenail selenium concentrations and prostate cancer risk. Odds ratios of prostate cancer by selenium concentration were estimated using multivariable-adjusted conditional logistic regression. All statistical tests were two-sided. RESULTS: Blood selenium was not associated with the risk of total prostate cancer (multivariable-adjusted odds ratio [OR] per 80 percentile increase = 1.01, 95% confidence interval [CI] = 0.83 to 1.23, based on 4527 case patients and 6021 control subjects). However, there was heterogeneity by disease aggressiveness (ie, advanced stage and/or prostate cancer death, Pheterogeneity = .01), with high blood selenium associated with a lower risk of aggressive disease (OR = 0.43, 95% CI = 0.21 to 0.87) but not with nonaggressive disease. Nail selenium was inversely associated with total prostate cancer (OR = 0.29, 95% CI = 0.22 to 0.40, Ptrend < .001, based on 1970 case patients and 2086 control subjects), including both nonaggressive (OR = 0.33, 95% CI = 0.22 to 0.50) and aggressive disease (OR = 0.18, 95% CI = 0.11 to 0.31, Pheterogeneity = .08). CONCLUSIONS: Nail, but not blood, selenium concentration is inversely associated with risk of total prostate cancer, possibly because nails are a more reliable marker of long-term selenium exposure. Both blood and nail selenium concentrations are associated with a reduced risk of aggressive disease, which warrants further investigation.

Higher serum 25-hydroxyvitamin D concentrations are related to a reduced risk of depression.

Vitamin D has been suggested to protect against depression, but epidemiological evidence is scarce. The present study investigated the relationship of serum 25-hydroxyvitamin D (25(OH)D) with the prevalence of depressive and anxiety disorders. The study population consisted of a representative sample of Finnish men and women aged 30-79 years from the Health 2000 Survey. The sample included 5371 individuals, of which 354 were diagnosed with depressive disorder and 222 with anxiety disorder. Serum 25(OH)D concentration was determined from frozen samples. In a cross-sectional study, a total of four indicators of depression and one indicator of anxiety were used as dependent variables. Serum 25(OH)D was the risk factor of interest, and logistic models used further included sociodemographic and lifestyle variables as well as indicators of metabolic health as confounding and/or effect-modifying factors. The population attributable fraction (PAF) was estimated. Individuals with higher serum 25(OH)D concentrations showed a reduced risk of depression. The relative odds between the highest and lowest quartiles was 0.65 (95% CI 0.46, 0.93; P for trend = 0.006) after adjustment for sociodemographic, lifestyle and metabolic factors. Higher serum 25(OH)D concentrations were associated with a lower prevalence of depressive disorder especially among men, younger, divorced and those who had an unhealthy lifestyle or suffered from the metabolic syndrome. The PAF was estimated to be 19% for depression when serum 25(OH)D concentration was at least 50 nmol/l. These results support the hypothesis that higher serum 25(OH)D concentrations protect against depression even after adjustment for a large number of sociodemographic, lifestyle and metabolic factors. Large-scale prospective studies are needed to confirm this finding.

Association between the intake of α-linolenic acid and the risk of CHD.

The intake of the mainly plant-derived n-3 PUFA α-linolenic acid (ALA) has been reported to be associated with a lower risk of CHD. However, the results have been inconsistent. Therefore, the objective of the present study was to examine the association between the intake of ALA and the risk of CHD. Potential effect modification by the intake of long-chain n-3 PUFA (n-3 LCPUFA) was also investigated. Data from eight American and European prospective cohort studies including 148 675 women and 80 368 men were used. The outcome measure was incident CHD (CHD event and death). During 4-10 years of follow-up, 4493 CHD events and 1751 CHD deaths occurred. Among men, an inverse association (not significant) between the intake of ALA and the risk of CHD events and deaths was observed. For each additional gram of ALA consumed, a 15 % lower risk of CHD events (hazard ratios (HR) 0·85, 95 % CI 0·72, 1·01) and a 23 % lower risk of CHD deaths (HR 0·77, 95 % CI 0·58, 1·01) were observed. No consistent association was observed among women. No effect modification by the intake of n-3 LCPUFA was observed.

Reduced risk of Parkinson's disease associated with lower body mass index and heavy leisure-time physical activity.

The risk factors for Parkinson's disease (PD) are not well established. We therefore examined the prediction of various lifestyle factors on the incidence of PD in a cohort drawn from the Finnish Mobile Clinic Health Examination Survey, conducted in 1973-1976. The study population comprised 6,715 men and women aged 50-79 years and free of PD at the baseline. All of the subjects completed a baseline health examination (including height and weight measurements) and a questionnaire providing information on leisure-time physical activity, smoking, and alcohol consumption. During a 22-year follow-up, 101 incident cases of PD occurred. The statistical analyses were based on Cox's model including age, sex, education, community density, occupation, coffee consumption, body mass index (BMI), leisure-time physical activity, smoking and alcohol consumption as independent variables. At first, BMI was not associated with PD risk, but after exclusion of the first 15 years of follow-up, an elevated risk appeared at higher BMI levels (P for trend 0.02). Furthermore, subjects with heavy leisure-time physical activity had a lower PD risk than those with no activity [relative risk (RR) 0.27, 95 % confidence interval (CI) 0.08-0.90]. In variance with findings for other chronic diseases, current smokers had a lower PD risk than those who had never smoked (RR 0.23, 95 % CI 0.08-0.67), and individuals with moderate alcohol intake (at the level of <5 g/day) had an elevated PD risk compared to non-drinkers. The results support the hypothesis that lifestyle factors predict the occurrence of Parkinson's disease, but more research is needed.

Self-administered questionnaire is a reliable measure of coffee consumption.

BACKGROUND: The objective of this study was to assess the agreement and repeatability of 2 methods of measuring habitual coffee consumption, and to examine their homogeneity with respect to socioeconomic and lifestyle factors. METHODS: Data on coffee consumption were collected from 4254 subjects by means of a health questionnaire (HQ) and a 1-year dietary history interview (DHI), the latter of which was used as the reference method during the Finnish Mobile Clinic Health Examination Survey conducted in 1973-1976. Short-term repeatability of the methods was assessed using data from 286 and 93 subjects who repeated the HQ and the DHI, respectively, after an interval of 4 to 8 months. The strength of agreement between the 2 methods and between the repeated measurements was estimated using intraclass correlation coefficients (ICCs). RESULTS: The ICC was 0.86 for the agreement between the HQ and the DHI, and 0.77 and 0.85 for the repeatability of the HQ and the DHI, respectively. There were no statistically significant systematic differences in mean intake values between the 2 methods or between repeated measurements. In subgroup analysis of background variables, there were only minor differences in agreement and repeatability, with somewhat higher ICC values among subjects with a healthier lifestyle and higher education. CONCLUSIONS: The high reliability and homogeneity of the health questionnaire make it a useful tool for measuring habitual coffee consumption for the purposes of epidemiological research.

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.

Major types of dietary fat and risk of coronary heart disease: a pooled analysis of 11 cohort studies.

BACKGROUND: Saturated fatty acid (SFA) intake increases plasma LDL-cholesterol concentrations; therefore, intake should be reduced to prevent coronary heart disease (CHD). Lower habitual intakes of SFAs, however, require substitution of other macronutrients to maintain energy balance. OBJECTIVE: We investigated associations between energy intake from monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), and carbohydrates and risk of CHD while assessing the potential effect-modifying role of sex and age. Using substitution models, our aim was to clarify whether energy from unsaturated fatty acids or carbohydrates should replace energy from SFAs to prevent CHD. DESIGN: This was a follow-up study in which data from 11 American and European cohort studies were pooled. The outcome measure was incident CHD. RESULTS: During 4-10 y of follow-up, 5249 coronary events and 2155 coronary deaths occurred among 344,696 persons. For a 5% lower energy intake from SFAs and a concomitant higher energy intake from PUFAs, there was a significant inverse association between PUFAs and risk of coronary events (hazard ratio: 0.87; 95% CI: 0.77, 0.97); the hazard ratio for coronary deaths was 0.74 (95% CI: 0.61, 0.89). For a 5% lower energy intake from SFAs and a concomitant higher energy intake from carbohydrates, there was a modest significant direct association between carbohydrates and coronary events (hazard ratio: 1.07; 95% CI: 1.01, 1.14); the hazard ratio for coronary deaths was 0.96 (95% CI: 0.82, 1.13). MUFA intake was not associated with CHD. No effect modification by sex or age was found. CONCLUSION: The associations suggest that replacing SFAs with PUFAs rather than MUFAs or carbohydrates prevents CHD over a wide range of intakes.

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.

Antioxidant vitamins and coronary heart disease risk: a pooled analysis of 9 cohorts.

BACKGROUND: Epidemiologic studies have suggested a lower risk of coronary heart disease (CHD) at higher intakes of fruit, vegetables, and whole grain. Whether this association is due to antioxidant vitamins or some other factors remains unclear. OBJECTIVE: We studied the relation between the intake of antioxidant vitamins and CHD risk. DESIGN: A cohort study pooling 9 prospective studies that included information on intakes of vitamin E, carotenoids, and vitamin C and that met specific criteria was carried out. During a 10-y follow-up, 4647 major incident CHD events occurred in 293 172 subjects who were free of CHD at baseline. RESULTS: Dietary intake of antioxidant vitamins was only weakly related to a reduced CHD risk after adjustment for potential nondietary and dietary confounding factors. Compared with subjects in the lowest dietary intake quintiles for vitamins E and C, those in the highest intake quintiles had relative risks of CHD incidence of 0.84 (95% CI: 0.71, 1.00; P=0.17) and 1.23 (1.04, 1.45; P=0.07), respectively, and the relative risks for subjects in the highest intake quintiles for the various carotenoids varied from 0.90 to 0.99. Subjects with higher supplemental vitamin C intake had a lower CHD incidence. Compared with subjects who did not take supplemental vitamin C, those who took >700 mg supplemental vitamin C/d had a relative risk of CHD incidence of 0.75 (0.60, 0.93; P for trend <0.001). Supplemental vitamin E intake was not significantly related to reduced CHD risk. CONCLUSIONS: The results suggest a reduced incidence of major CHD events at high supplemental vitamin C intakes. The risk reductions at high vitamin E or carotenoid intakes appear small.

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.