Abstract 1032: Role of Heavy Metals in Association Between Smoking and Cardiovascular Disease: Results From NHANES 1999–2006
Cigarette smoke consists of wide variety of substances, many of which have been implicated in cardiovascular morbidity. We aim to assess role of lead and cadmium exposure as partial mediators in the association between smoking and composite cardiovascular and cerebrovascular disease (CCVD).
Methods Cross-sectional data from National Health and Nutritional Examination Survey 1999 –2006 were used. The composite outcome CCVD was determined using standardized questionnaire asking about history of stroke, angina, heart attack, coronary artery disease and congestive heart failure. Active smoking was defined as self reported current smoking or measured serum cotinine > 10 ng/mL. Serum lead and cadmium levels were measured by atomic absorption spectrometry.
Results After adjustment of demographic and cardiovascular risk factors, odds ratios (OR) (95%CI) for CCVD comparing quartiles 2 to 4 of serum lead levels with the lowest quartile were found to be 1.01 (0.72–1.43), 1.29 (0.92–1.82) and 1.39 (1.03–1.89) (p for trend 0.04). The corresponding ORs (95% CI) for cadmium were 1.23 (0.97–1.56), 1.42 (1.06 –1.89) and 1.96 (1.45–2.67) (p for trend <0.001). Table 1⇓ demonstrates the effect of adjustment for lead and/or cadmium upon the OR between smoking and CCVD. OR for active smokers in comparison to never smokers was 2.05 (1.58 –2.67). Adjustment for lead did not significantly affect the OR but adjustment for cadmium significantly reduced the OR to 1.46 (1.07–1.98) (p=0.03). Stratifying the population by serum cotinine levels, similar reduction in OR was observed after adjustment for serum cadmium level among categories with serum cotinine > 10 ng/mL (active smoking range). Adjustment for lead alone, however, did not significantly affect the association between smoking and CCVD.
Conclusions High levels of lead (>2.5 microgram/dL) and cadmium (>0.4 microgram/L) were found to be associated with CCVD. The relationship of smoking and CCVD may be partially mediated through cadmium