Association of hypoadiponectinemia with smoking habit in men

Adiponectin is emerging as an important molecule in obesity, the metabolic syndrome, and cardiovascular disease. On the other hand, smoking habit is well known to be related to cardiovascular disease and hypertension. To examine the association between adiponectin concentration and smoking habit, we performed an epidemiological survey and an acute exposure test in humans and an experiment in adipocytes to elucidate the mechanism underlying the association between adiponectin and smoking. In the epidemiological study, we enrolled a total of 331 male subjects to examine chronic smoking exposure. Plasma adiponectin was significantly lower ( P = 0.01) in current smokers ( 5.3 +/- 0.3 mu g/mL) than in never-smokers (6.5 +/- 0.4 mu g/mL). A significant association between smoking and low adiponectin level was also confirmed in multiple regression analysis including age, body mass index, hypertension, diabetes, hyperlipidemia, and creatinine clearance ( never- smokers 6.5 +/- 0.4 mu g/mL; past smokers 5.6 +/- 0.3 mu g/mL; current smokers 5.2 +/- 0.4 mu g/mL; F = 4.52; P = 0.01). To examine the acute effect of smoking on adiponectin concentration for 12 hours, we measured plasma adiponectin level in 5 male never- smokers before smoking and 3, 6, and 12 hours after smoking, with the result that adiponectin showed a significant decrease after smoking ( 12 hours; - 14.5 +/- 0.6%; P < 0.01). In cultured mouse 3T3-L1 adipocytes, H2O2 and nicotine reduced the mRNA expression and secretion of adiponectin in a dose-dependent manner. Smoking habit is associated with adiponectin concentration in men, and its suppressive effect is mediated in part through direct inhibition of smoking on adiponectin expression in adipocytes.