Relationship between mild-to-moderate chronic kidney disease and decreased bone mineral density in Chinese adult population.

Background: Several studies have shown ethnic differences in bone and mineral metabolism in healthy people and patients with chronic kidney disease (CKD). However, there have been few studies regarding CKD and bone mineral density (BMD) in Chinese population. We aimed to explore the relationship between mild-to-moderate CKD and decreased BMD in Chinese adult population.

Methods: A total of 24,002 adults were enrolled in this cross-sectional study. Mild-to-moderate CKD was defined as 30 < estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2) or eGFR ≥ 60 mL/min/1.73 m(2) with proteinuria greater than 1+. BMD was measured by dual-energy X-ray absorptiometry at the lumbar spine. Either osteopenia or osteoporosis was defined as decreased BMD. Multivariate logistic regression analysis was used to estimate the associations with decreased BMD.

Results: The subjects comprised 71.5 % men and 28.5 % women, the age was 49.9 ± 13.9 years. The overall prevalence of CKD was 2.9 %. Decreased BMD was 22.1, 19.9 % had osteopenia, and 2.2 % had osteoporosis. The percentage of patients with decreased BMD, osteopenia and osteoporosis were statistically higher (P < 0.05) in CKD patients compared with those of non-CKD participants, which was 29.5 versus 21.9 %, 25.9 versus 19.8 % and 3.6 versus 2.1 %, respectively. The risk for decreased BMD increased with CKD in a simple logistic analysis. However, the correlation disappeared after adjusted for age, sex, smoking, drinking, hypertension, diabetes and obesity.

Conclusions: Subjects with worse renal function have significantly lower BMD, but after adjusted for confounders, mild-to-moderate CKD is not independently associated with decreased BMD.