Smoking and hyperparathyroidism in patients with end-stage renal disease (ESRD)

Background and methods: Smoking is associated with hyperparathyroidism in the elderly general population and nicotine, the main component of tobacco smoke, stimulates PTH release in experimental models. Although smoking is a persisting problem in patients with end-stage renal disease (ESRD), the association between smoking and PTH has never been specifically examined in these patients. We investigated the relationship between smoking and hyperparathyroidism in a well-characterized group of 161 nondiabetic dialysis patients. Results: Sixty-four patients (40%) were smokers. Heavy smokers had higher intact PTH (median: 280 pg/mL) and PTH1-84 (188 pg/mL) than light smokers (180 pg/mL and 95 pg/mL) and nonsmokers (169 pg/mL and 95 pg/mL). In a multiple regression analysis, smoking was independently associated with intact PTH (beta=0.29, p=0.002) and PTH1-84 (beta=0.29, p=0.002). Fifty-six of 161 patients (35%) were classified as having hyperparathyroidism. In a multiple logistic regression model the odds of hyperparathyroidism were about 4 times higher in heavy smokers (odds ratio 3.88, 95% CI 1.16-12.92, p=0.027) than in nonsmokers. Conclusion: In dialysis patients heavy smoking is independently associated with high levels of intact PTH and PTH1-84. Further observational, mechanistic and interventional studies are needed to assess the nature (causal or noncausal) of these links in ESRD.