A Western Diet Pattern Is Associated with Higher Concentrations of Blood and Bone Lead among Middle-Aged and Elderly Men

Background: Little is known about the effects of overall dietary pattern on lead concentration.Objective: We examined the association of overall dietary patterns, derived from a semiquantitative food frequency questionnaire, with bone and blood lead concentrations.Methods: These longitudinal analyses included mostly non-Hispanic white, middle-aged-to-elderly men from the Veterans Affairs Normative Aging Study. Long-term lead exposures were measured as tibia and patella lead concentrations by using K-shell-X-ray fluorescence. Short-term lead exposures were measured as blood lead concentrations by using graphite furnace atomic absorption spectroscopy. Dietary pattern scores were derived by using factor analysis. Linear mixed-effects models were utilized to predict blood lead concentrations among 983 men, aged 44-92 y at baseline, with a total of 3273 observations (during 1987-2008). We constructed linear regression models to determine the relations between dietary patterns and bone lead concentrations among 649 participants with an age range of 49-93 y.Results: Two major dietary patterns were identified: a prudent dietary pattern, characterized by high intakes of fruit, legumes, vegetables, whole grains, poultry, and seafood; and a Western dietary pattern, characterized by high intakes of processed meat, red meat, refined grains, high-fat dairy products, French fries, butter, and eggs. After adjusting for age, smoking status, body mass index, total energy intake, education, occupation, neighborhood-based education and income level, men in the highest tertile of the Western pattern score (compared with the lowest) had 0.91 μg/dL (95% CI: 0.41, 1.42 μg/dL) higher blood lead, 5.96 μg/g (95% CI: 1.76, 10.16 μg/g) higher patella lead, and 3.83 μg/g (95% CI: 0.97, 6.70 μg/g) higher tibia lead. No significant association was detected with the prudent dietary pattern in the adjusted model.Conclusions: These findings suggest that the Western diet is associated with a greater lead body burden among the middle-aged-to-elderly men. More studies are needed to examine the underlying mechanisms by which dietary patterns are associated with lead concentrations.

Chemerin levels as predictor of acute coronary events: a case-control study nested within the veterans affairs normative aging study

OBJECTIVE

Chemerin is a recently identified adipocytokine that has been positively correlated with the presence and severity of coronary artery disease (CAD). However, no studies have examined circulating chemerin levels as a predictor of acute coronary syndrome (ACS). The purpose of this study is to evaluate whether chemerin levels predict the onset of ACS.

MATERIALS/METHODS

We studied 90 men whose serum had been collected at least 2 years before the development of ACS, and 162 controls matched with the cases in a 1:2 fashion for age and year of collection. The mean age of the cohort was 66.3±9.6 years (range 34-84 years). Serum chemerin levels were measured with a commercially available enzyme-linked immunosorbent assay.

RESULTS

Age was positively associated with chemerin levels (r=0.39, p<0.001). Logistic regression analysis, adjusting for years since blood collection, demonstrated a null association between chemerin levels and the odds ratio for development of ACS (OR: 0.99, 95% CI [0.99-1.001]). This association remained null after adjusting for age (OR: 0.99 95% CI [0.99-1.001]).

CONCLUSIONS

Although cross-sectional and case-control studies suggest a positive association between chemerin levels and CAD, we demonstrate that chemerin levels do not predict the development of ACS.

Lead exposure and fear-potentiated startle in the VA Normative Aging Study: a pilot study of a novel physiological approach to investigating neurotoxicant effects

BACKGROUND

Physiologically-based indicators of neural plasticity in humans could provide mechanistic insights into toxicant actions on learning in the brain, and perhaps prove more objective and sensitive measures of such effects than other methods.

OBJECTIVES

We explored the association between lead exposure and classical conditioning of the acoustic startle reflex (ASR)-a simple form of associative learning in the brain-in a population of elderly men. Fifty-one men from the VA Normative Aging Study with cumulative bone lead exposure measurements made with K-X-Ray-Fluorescence participated in a fear-conditioning protocol.

RESULTS

The mean age of the men was 75.5years (standard deviation [sd]=5.9) and mean patella lead concentration was 22.7μg/g bone (sd=15.9). Baseline ASR eyeblink response decreased with age, but was not associated with subsequent conditioning. Among 37 men with valid responses at the end of the protocol, higher patella lead was associated with decreased awareness of the conditioning contingency (declarative learning; adjusted odds ratio [OR] per 20μg/g patella lead=0.91, 95% confidence interval [CI]: 0.84, 0.99, p=0.03). Eyeblink conditioning (non-declarative learning) was 0.44sd less (95% CI: -0.91, 0.02; p=0.06) per 20μg/g patella lead after adjustment. Each result was stronger when correcting for the interval between lead measurement and startle testing (awareness: OR=0.88, 95% CI: 0.78, 0.99, p=0.04; conditioning: -0.79sd less, 95% CI: -1.56, 0.03, p=0.04).

CONCLUSIONS

This initial exploration suggests that lead exposure interferes with specific neural mechanisms of learning and offers the possibility that the ASR may provide a new approach to physiologically explore the effects of neurotoxicant exposures on neural mechanisms of learning in humans with a paradigm that is directly comparable to animal models.