Omega-6 polyunsaturated fatty acids, serum zinc, delta-5- and delta-6-desaturase activities and incident metabolic syndrome.

BACKGROUND: The associations of n-6 polyunsaturated fatty acids (PUFA) with metabolic syndrome have been poorly explored. We investigated the associations of the serum n-6 PUFA and the activities of enzymes involved in the PUFA metabolism, delta-5-desaturase (D5D) and delta-6-desaturase (D6D) with risk of incident metabolic syndrome. We also investigated whether zinc, a cofactor for these enzymes, modifies these associations. METHODS: A prospective follow-up study was conducted on 661 men who were aged 42-60 years old at baseline in 1984-1989 and who were re-examined in 1998-2001. RESULTS: Men in the highest versus the lowest serum total omega-6 PUFA tertile had a 70% lower multivariate-adjusted risk of incident metabolic syndrome [odds ratio (OR) = 0.30; 95% confidence interval (CI) = 0.18-0.51, Ptrend < 0.001]. Inverse associations were also observed for linoleic acid, arachidonic acid and D5D activity. By contrast, men in the highest tertile of D6D activity had an 84% higher risk (OR = 1.84; 95% CI = 1.15-2.94, Ptrend = 0.008). Similar associations were observed with many of the metabolic syndrome components at the re-examinations. Most associations were attenuated after adjustment for body mass index. Finally, the associations of D6D and LA were stronger among those with a higher serum zinc concentration. CONCLUSIONS: Higher serum total n-6 PUFA, linoleic acid and arachidonic acid concentrations and D5D activity were associated with a lower risk of developing metabolic syndrome and higher D6D activity was associated with a higher risk. The role of zinc also needs to be investigated in other populations.

Dietary intake of polyunsaturated fatty acids and risk of hip fracture in men and women.

UNLABELLED: Data on the impact of polyunsaturated fatty acid intake on hip fracture risk are inconsistent. We investigated this association in 75,878 women and 46,476 men and did not find a significant role for polyunsaturated fatty acid intake in the prevention of hip fractures. INTRODUCTION: Polyunsaturated fatty acids (PUFA) are important in the prevention of chronic diseases, but studies of bone health report inconsistent results. Our aim was to investigate the association between dietary PUFA intake and risk of hip fracture in two large prospective cohorts of men and women with long follow-up times and frequently updated dietary data. METHODS: The study population included 75,878 women and 46,476 men free of osteoporosis at baseline. Dietary intakes were assessed by a food frequency questionnaire at baseline and several times during the follow-up. Multivariable-adjusted Cox proportional hazards models were used to estimate relative risks (RR). RESULTS: During 24 years of follow-up, we identified 1,051 hip fracture cases due to low or moderate trauma among the women and 529 cases among the men. In the pooled analyses, no statistically significant associations were found between intakes of total PUFA [RR in the highest vs. lowest quintile: 0.99, 95% confidence interval (CI) 0.69, 1.43; p value for trend is =0.83], total n-3 PUFA (RR 0.89, 95% CI 0.75, 1.06; p value for trend is =0.26), total n-6 PUFA (RR 0.99, 95% CI 0.71, 1.38; p value for trend is =0.82), n-6/n-3 PUFA ratio or individual PUFAs, and hip fracture risk. However, in women low intakes of total PUFA, total n-6 PUFA, and linoleic acid were associated with higher risk. CONCLUSIONS: This study does not support a significant role for PUFA intake in the prevention of hip fractures, although low total PUFA, n-6 PUFA, or linoleic acid intakes may increase the risk in women.

Glycemic index, glycemic load, and the risk of acute myocardial infarction in Finnish men: the Kuopio Ischaemic Heart Disease Risk Factor Study.

BACKGROUND AND AIM: The role of dietary glycemic index (GI) and glycemic load (GL) in coronary heart disease (CHD) is unclear. Our aim was to study the association between the dietary GI and GL and the risk of acute myocardial infarction (AMI). METHODS AND RESULTS: The study population consisted of 1981 Finnish men from the prospective population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study, aged 42-60 years and free of CHD at baseline. During an average follow-up time of 16.1 years, 376 new AMI events occurred. In multivariable-adjusted Cox proportional hazards models, the relative risk (RR) for AMI in the highest quartile of GI was 1.25 (95% CI: 0.92-1.69; P for trend=0.08) and for GL 1.11 (95% CI: 0.79-1.57; P for trend=0.21) when compared with the lowest quartile. For overweight (BMI ≥ 27.5 kg/m²) men, the multivariable-adjusted RR for AMI in the highest compared to the lowest tertile of GI and GL were 1.58 (95% CI: 1.03-2.43; P for trend=0.04, P for interaction=0.01) and 2.05 (95% CI: 1.30-3.23; P for trend=0.002, P for interaction=0.002), respectively. For physically less active men; energy expenditure for leisure-time physical activity < 50 kcal/d, the RR for AMI was 1.72 (95% CI: 1.07-2.76; P for trend=0.04, P for interaction 0.80) with higher GL. CONCLUSIONS: Our results suggest that both high dietary GI and GL are associated with increased risk of AMI among overweight and GL possibly among less physically active men.

Serum Concentrations of 25-Hydroxyvitamin D and Depression in a General Middle-Aged to Elderly Population in Finland.

OBJECTIVES: Low concentrations of serum 25-hydroxyvitamin D [25(OH)D] have been postulated to associate with an increased prevalence of depression. As there are a limited number of publications on this issue, we examined the association between serum 25(OH)D and depression in a general middle-aged or older population. DESIGN: A population-based cross-sectional study. SETTING AND PARTICIPANTS: A total of 1602 men and women from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) in Eastern Finland, aged 53-73 y in 1998-2001, were analysed. MEASUREMENTS: Depressive symptoms were assessed with the DSM-III depression scale, and those individuals who had scores over 4 (range 0-12) or had reported undergoing current antidepressant therapy, were considered as suffering from depression. Associations were estimated in serum 25(OH)D tertiles using logistic regression. RESULTS: Among the participants, 183 subjects (11.4%) were considered to have depression. The mean age of the subjects was 62.6 years (SD 6.4, range 53.4-73.8 years). The mean serum 25(OH)D concentration was 43.8 nmol/L (SD 17.7, range 8.5-112.8 nmol/L), concentrations <50 nmol/L were observed in 65.0% of the subjects, and only 5.0% displayed concentrations ≥75 nmol/L. After multivariable adjustments, the odds ratios for having depression in the tertiles (from highest to the lowest) of serum 25(OH)D were 1, 1.35 (95 % CI: 0.87, 2.09) and 1.64 (95 % CI: 1.03, 2.59), P for trend=0.036. CONCLUSION: These findings indicate that a lower concentration of serum 25(OH)D is associated with a higher prevalence of depression in an elderly general population.

Associations of serum n-3 and n-6 polyunsaturated fatty acids with plasma natriuretic peptides.

BACKGROUND/OBJECTIVES: The n-3 and n-6 polyunsaturated fatty acids (PUFAs) have been associated with lower risk of cardiovascular disease (CVD), but little is known about their association with natriuretic peptides (NPs), a marker for CVD risk. The aim of this study was to investigate the association of serum n-3 and n-6 PUFAs with NPs. SUBJECTS/METHODS: A cross-sectional analysis of the association between serum n-3 and n-6 PUFAs with plasma N-terminal atrial (NT-proANP) and brain (NT-proBNP) NPs in a population-based sample of 985 men aged 46-65 years from Eastern Finland. RESULTS: After adjustment for age and examination year, only serum n-6 PUFA arachidonic acid (ARA) was inversely associated with NT-proANP (P-trend across quartiles=0.02), but further adjustments for conventional risk factors (body mass index, smoking, alcohol intake, systolic blood pressure, low-density lipoprotein cholesterol and history of CVD) attenuated the association (P-trend=0.10). The associations with the other PUFAs were not statistically significant. Among the PUFAs, only serum n-3 PUFA docosapentaenoic acid (DPA; P-trend=0.03) and ARA (P-trend=0.02) had inverse associations with NT-proBNP after adjustment for age and examination years. The associations were again attenuated after further adjustments but remained statistically significant for DPA (P-trend=0.05). Our results also suggested that the inverse associations may be more evident among those using beta-blockers. CONCLUSIONS: Our study suggests little overall impact of serum n-3 or n-6 PUFAs on plasma NPs.

Association between serum long-chain omega-3 polyunsaturated fatty acids and cognitive performance in elderly men and women: The Kuopio Ischaemic Heart Disease Risk Factor Study.

BACKGROUND/OBJECTIVES: Fish intake and the long-chain omega-3 polyunsaturated fatty acids (PUFAs) in fish have been suggested to lower the risk of cognitive decline. We assessed whether serum long-chain omega-3 PUFAs eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) are associated with performance on neuropsychological tests in an older population and whether exposure to methylmercury, mainly from fish, or apolipoprotein-E4 (Apo-E4) phenotype can modify the associations. SUBJECTS/METHODS: A total of 768 participants from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study were included. Cognitive function was measured using five neuropsychological tests: the Trail Making Test, the Verbal Fluency Test, the Selective Reminding Test, the Visual Reproduction Test and the Mini Mental State Exam. Multivariate-adjusted analysis of covariance and linear regression were used to analyze the cross-sectional associations. RESULTS: We found statistically significant associations between serum EPA+DPA+DHA and better performance in the Trail Making Test and the Verbal Fluency Test. The individual associations with EPA and DHA were similar with the findings with EPA+DPA+DHA, although the associations with DHA were stronger. No associations were observed with serum DPA. Pubic hair mercury content was associated only with a worse performance in the Trail Making Test, and mercury had only little impact on the associations between the serum PUFAs and cognitive performance. Apo-E4 phenotype did not modify the associations with PUFAs or mercury. CONCLUSIONS: Higher serum long-chain omega-3 PUFA concentrations were associated with better performance on neuropsychological tests of frontal lobe functioning in older men and women. Mercury exposure or Apo-E4 phenotype had little impact on cognitive performance.

Serum long-chain omega-3 polyunsaturated Fatty acids and future blood pressure in an ageing population.

OBJECTIVES: To investigate the associations of serum long-chain omega-3 polyunsaturated fatty acids (PUFA) and hair mercury with future blood pressure in an ageing population. DESIGN: Prospective study with baseline measurements in 1998-2001 and follow-up measurements in 2005-2008. The linear relationships (ß) of baseline serum fatty acids and hair mercury with future systolic and diastolic blood pressure and pulse pressure were analyzed with multiple linear regression models, using log-transformed values. PARTICIPANTS: 181 men and 200 women aged 53-73 y from the Kuopio Ischemic Heart Disease Risk Factor Study (KIHD) population in Eastern Finland, who were free of cardiovascular disease, diabetes or hypertension at baseline. MEASUREMENTS: Total serum esterified and nonesterified fatty acids and pubic hair mercury were used as markers for exposure. Anthropometric and other lifestyle and health-related data were collected. RESULTS: The mean serum concentrations were 1.67% (SD 0.92) for eicosapentaenoic acid (EPA), 0.79% (SD 0.16) for docosapentaenoic acid (DPA) and 2.78 (SD 0.92) for docosahexaenoic acid (DHA), of all serum fatty acids. The mean hair mercury concentration was 1.5 µg/g (SD 1.6). We did not find statistically significant associations between the baseline serum long-chain omega-3 PUFA concentrations or hair mercury content and future blood pressure. Hair mercury did not modify the associations with the long-chain omega-3 PUFAs, either. CONCLUSIONS: Higher serum long-chain omega-3 PUFA concentration, a biomarker of fish or fish oil consumption, may not have an impact on future blood pressure in an ageing population.

Association of serum n-3 polyunsaturated fatty acids with C-reactive protein in men.

BACKGROUND/OBJECTIVES: N-3 polyunsaturated fatty acids (PUFAs) have been associated with reduced inflammation. We tested the hypothesis that high serum concentrations of the n-3 PUFAs are associated with lower serum C-reactive protein (CRP) concentrations in healthy middle-aged Finnish men. We also examined whether exposure to mercury, an environmental contaminant in fish, which is also a major source of long-chain n-3 PUFA, was associated with CRP. SUBJECTS/METHODS: Data from the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor Study were analyzed cross-sectionally to determine the associations between serum n-3 PUFAs, hair mercury and serum CRP in 1395 healthy men, aged 42-60 years. Linear regression analyses were performed to analyze the associations. RESULTS: In the multivariate models, the mean serum CRP in quartiles of serum total n-3 PUFA concentration was 1.23, 1.27, 1.18 and 1.08 mg/l, P for trend = 0.01. Statistically significant inverse associations were also observed with the total serum long-chain n-3 PUFA concentration and with the individual long-chain n-3 PUFAs docosapentaenoic acid and docosahexaenoic acid, but not with eicosapentaenoic acid or with the intermediate-chain n-3 PUFA alpha-linolenic acid. Hair methylmercury content was not associated with serum CRP levels and it did not modify the associations between serum n-3 PUFAs and CRP either. CONCLUSIONS: Serum n-3 PUFAs and especially the long-chain n-3 PUFA concentration, a marker of fish or fish oil consumption, were inversely associated with serum CRP in men. Exposure to mercury was not associated with serum CRP.

Fish consumption and risk of subclinical brain abnormalities on MRI in older adults.

OBJECTIVE: To investigate the association between fish consumption and subclinical brain abnormalities. METHODS: In the population-based Cardiovascular Health Study, 3,660 participants age > or =65 underwent an MRI scan in 1992-1994. Five years later, 2,313 were scanned. Neuroradiologists assessed MRI scans in a standardized and blinded manner. Food frequency questionnaires were used to assess dietary intakes. Participants with known cerebrovascular disease were excluded from the analyses. RESULTS: After adjustment for multiple risk factors, the risk of having one or more prevalent subclinical infarcts was lower among those consuming tuna/other fish > or =3 times/week, compared to <1/month (relative risk 0.74, 95% CI = 0.54-1.01, p = 0.06, p trend = 0.03). Tuna/other fish consumption was also associated with trends toward lower incidence of subclinical infarcts. Additionally, tuna/other fish intake was associated with better white matter grade, but not with sulcal and ventricular grades, markers of brain atrophy. No significant associations were found between fried fish consumption and any subclinical brain abnormalities. CONCLUSIONS: Among older adults, modest consumption of tuna/other fish, but not fried fish, was associated with lower prevalence of subclinical infarcts and white matter abnormalities on MRI examinations. Our results add to prior evidence that suggest that dietary intake of fish with higher eicosapentaenoic acid and docosahexaenoic acid content, and not fried fish intake, may have clinically important health benefits.

Homocysteine as a risk factor for CVD mortality in men with other CVD risk factors: the Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study.

OBJECTIVE: Based on case-control and prospective studies elevated blood total homocysteine (tHcy) has been suggested to be an independent risk factor for cardiovascular diseases (CVD). The purpose of the study was to explore the joint effect of increased serum tHcy concentration and other risk factors on the risk of CVD mortality in middle-aged men without a history of heart disease or stroke. DESIGN: A prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study. SETTING: Eastern Finland. Subjects. A total of 802 men aged 46-64 years, examined in 1991-93. MAIN OUTCOME MEASURES: CVD mortality event. RESULTS: The mean serum tHcy concentration was 10.8 micromol L(-1) (SD 3.3). During the average follow-up time of 10.8 years 50 men experienced a CVD death. The hazard rate ratio for CVD mortality was 1.80 (95% confidence interval: 1.02-3.19) in men in the highest serum tHcy third versus lower thirds after adjustment for cardiovascular risk factors. Furthermore, elevated serum tHcy concentration appeared to increase the risk of CVD death in men who smoke or who have high circulating concentrations of serum total or LDL cholesterol, apo-B apolipoprotein or plasma fibrinogen. CONCLUSION: We conclude that homocysteine may increase the risk of CVD mortality in middle-aged men from Eastern Finland, and it may especially increase the risk when present with other risk factors for CVD.