Obesity is associated with secondary hyperparathyroidism in men with moderate and severe chronic kidney disease.

BACKGROUND AND OBJECTIVES Obesity is associated with secondary hyperparathyroidism in the general population. The objective of this study is to explore whether the same association is present in patients with chronic kidney disease. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS Linear regression models were used to examine the association between intact parathyroid hormone level and body mass index in 496 male US veterans (age 69.4 +/- 10.2 yr, 22.8% black) who had chronic kidney disease stages 2 to 5 and were not yet on dialysis (estimated GFR 31.8 +/- 11.2 ml/min per 1.73 m2). RESULTS Higher intact parathyroid hormone was associated with higher body mass index after adjustment for age, race, diabetes, and serum calcium and phosphorus levels. This association was independent of age, race, diabetes status, and serum calcium and phosphorus but was limited to patient groups with lower albumin (P = 0.005 for the interaction term) or higher white blood cell count (P = 0.026 for the interaction term). CONCLUSIONS Higher body mass index is associated with secondary hyperparathyroidism in patients who have chronic kidney disease and are not yet on dialysis, especially in patients with evidence of malnutrition and inflammation. Confirmation of these findings in other patient groups with chronic kidney disease and better characterization of the underlying mechanisms of action will be necessary before advocating weight loss as a means to treat secondary hyperparathyroidism in chronic kidney disease.