Dietary patterns, bone lead and incident coronary heart disease among middle-aged to elderly men

摘要

Background: Most absorbed lead ends up in the bone, where it can be measured as a biomarker of cumulative exposure, elevations of which have been shown to predict a higher risk of coronary heart disease (CHD). Knowledge about the role of dietary patterns is critical to the development of effective interventions for the cardiovascular toxicity of cumulative lead exposure.Methods: 594 men, free of CHD at baseline, were followed from August 1991 to June 2011 in the Normative Aging Study. Bone lead concentrations were measured by K-shell -X-ray fluorescence. Dietary patterns were identified using principal components analysis. Two dietary patterns were identified: a 'prudent' pattern characterized by high intake of fruit, vegetables, legumes, tomatoes, poultry, and seafood; and a 'Western' pattern, with high intake of red meat, processed meat, refined grains, high-fat dairy products, high-energy drinks, fries, butter and eggs. Cox proportional hazard models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for incident CHD. Effect modification on the multiplicative scale was examined through cross product interaction terms.Results: 137 men developed incident CHD events during 5071 person-years of follow-up. After adjusting for age, body mass index, total energy intake, smoking status, total cholesterol to high-density lipoprotein ratio, education and occupation, an HR of incident CHD was 1.64 (95% CI: 1.27-2.11) with each doubling in patella lead concentration in the low prudent diet group ( median prudent score); and the HR decreased to 1.07 (95% CI: 0.86-1.34) in the high prudent diet (= median prudent score) (p-for-interaction = 0.01), suggesting protective effects of prudent diet against lead-related CHD. By contrast, the association between tibia lead and CHD was non-significantly larger in the low Western diet group (HR = 1.43, 95% CI: 1.14-1.80) compared with the high Western diet group (HR = 1.08, 95% CI: 0.86-1.34) (p-for-interaction = 0.06). No significant effect modifications were detected by Western diet in the patella lead-CHD association and by prudent diet in the tibia lead-CHD association.Conclusions: Prudent diet may reduce the risk of development of CHD in relation to patella lead. However, these findings need to be interpreted with caution, given the modest sample size.