Dietary n-3 polyunsaturated acids and smoking-related chronic obstructive pulmonary disease.

BACKGROUND: Fish contain n-3 polyunsaturated fatty acids, principally eicosapentaenoic acid and docosahexaenoic acid, which are known to interfere with the body's inflammatory response and may be of benefit in chronic inflammatory conditions. METHODS: We studied the relation between the dietary intake of n-3 fatty acids and chronic obstructive pulmonary disease (COPD) in 8960 current or former smokers participating in a population-based study of artheroscierosis. Intake of fatty acids was estimated with a dietary questionnaire. The presence of COPD was assessed by a questionnaire on respiratory symptoms and by spirometry. Three case definitions of COPD were used: symptoms of chronic bronchitis (667 subjects), physician-diagnosed emphysema reported by the subject (185 subjects), and spirometrically detected COPD (197 subjects). RESULTS: After control for pack-years of smoking, age, sex, race, height, weight, energy intake, and educational level docosahexaenoic acid was inversely related to the ris of COPD in a quantity-dependent fashion. The adjusted odds ratio for the highest quartile was 0.66 for chronic bronchitis (95 percent confidence interval, 0.52 to 0.85; P<0.001 for linear trend across the range of intake value), 0.31 for physician-diagnosed emphysema (95 percent confidence interval, 0.18 to 0.52; P for liner trend, 0.003), and 0.50 for spirometrically detected COPD (95 percent confidence interval, 0.32 to 0.79; P for linear trend, 0.007). CONCLUSION: A high dietary intake of n-3 fatty acids may protect cigarette smokers against COPD.

Risk of hospitalized stroke in men enrolled in the Honolulu Heart Program and the Framingham Study: A comparison of incidence and risk factor effects.

BACKGROUND AND PURPOSE: Risk of death due to stroke in Japan is more than double the risk in the United States. It remains unknown why some ethnic groups are more prone to stroke than others. Our purpose was to compare the 20-year incidence of hospitalized stroke between Japanese-American men in the Honolulu Heart Program and white men in the Framingham Study. METHODS: This was a 20-year follow-up study beginning around 1965, a population-based study on the island of Oahu, Hawaii, and in Framingham, Mass. Participants were 7589 men in Honolulu and 1216 men in Framingham without prevalent coronary heart disease and stroke. Subjects were 45 to 68 years old when follow-up began. Main outcome measures were incident thromboembolic and hemorrhagic stroke. RESULTS: Framingham men had a 40% excess of thromboembolic stroke compared with Honolulu men after adjustment for age and other risk factors (62/1000 versus 45/1000, respectively, P<0.001), whereas incidence of hemorrhagic stroke was nearly identical (14.8/1000). In both cohorts, each stroke type was consistently elevated in the presence of hypertension and cigarette smoking. Diabetes and body mass index increased the risk of thromboembolic stroke in both samples, and diabetes increased the risk of hemorrhagic events in Framingham. Alcohol intake and low total cholesterol were associated with hemorrhagic events in Honolulu but not in Framingham. Despite occasional differences in risk factor effects, none were significantly different between cohorts. CONCLUSIONS: The incidence of thromboembolic stroke requiring hospitalization is markedly less in Honolulu than in Framingham. The difference in stroke incidence rates observed cannot be explained by the traditional risk factors. Further studies are needed to identify factors that protect Japanese-American men in Honolulu from stroke.

Heterogeneity among populations for familial aggregation of blood pressure.

A simple model of familial aggregation was applied to age-sex corrected systolic (SBP) and diastolic (DBP) blood pressure data from two separate studies: The Québec Family Study and the Tecumseh Community Health Study. Examination of the familial correlations suggested heterogeneity across studies in all DBP correlations, but for SBP only spouse correlations were higher in Québec. Fitting the path model to the data revealed that the only source of heterogeneity for SBP was in spouse resemblance (u), which was significant in Québec but could be dropped from the model in Tecumseh. For SBP, no further heterogeneity was detected, with the vertical transmission being compatible with (but not evidence for) purely polygenic inheritance (i.e., τf = τm = 1/2). Familiality estimates (t2 ) for SBP were quite high (nearly 40%), and extra sibling resemblance was significant. For DBP, heterogeneity was detected in all parameters of the model except for spouse resemblance. Common sibship environmental effects (b) were of little importance in Tecumseh but were highly significant in Québec. Vertical transmission from mothers (τm ) could be fixed at 1/2 in Tecumseh but was only about half as large in Québec, and familiality estimates were higher in Québec (nearly 60%) than in Tecumseh (about 25%). One source of the heterogeneity for SBP was due to cohabitation, which positively impacted on sibling correlations. The source of the sample heterogeneity in DBP may be through environmental factors which have a smaller impact in Tecumseh than in Québec, although genetic heterogeneity could not be ruled out. Differences in the study designs, as well as differences in the two populations, could account for the heterogeneity detected.