Among US adults, dietary and total intake of copper is positively correlated with increased bone mineral density (BMD) and negatively correlated with risk for osteoporosis, according to study results published in Biological Trace Element Research.
While previous studies have measured the association between serum copper and bone density, not many have analyzed the link between copper consumption and osteoporosis and BMD.
A team of researchers in China conducted a study using the National Health and Nutritional Examination Surveys (NHANES) to investigate the association between the intake of copper and the risk for osteoporosis in the US.
Levels of dietary and total copper intake were divided based on quartiles: quartile 1, less than 25th percentile; quartile 2, 25th to 50th percentile; quartile 3, 50th to 75th percentile; and quartile 4, more than the 75th percentile. Two models of logistic regression were used to estimate the odds ratio (OR) for the associations of copper intake with the risk for osteoporosis. The first model adjusted for age, sex, and race, and the second model adjusted further for all covariates of interest.
Of the 8224 participants in the study, 351 met the diagnosis criteria for osteoporosis; the overall weighted prevalence was 4.3%. Patients with vs without osteoporosis were more often older, more emaciated, more likely to be women, widowed, have hypertension, have a lower annual family income, and take prednisone or cortisone. Patients who did not have osteoporosis were found to have more dietary or total copper intake.
In model 1, ORs for the risk for osteoporosis and dietary copper intake across quartiles 3 and 4 compared with quartile 1 were 0.60 (95% CI, 0.39-0.92) and 0.52 (95% CI, 0.30-0.91), respectively, which were similar to results found in model 2. In model 2, the ORs for risk for osteoporosis and total copper intake across quartiles 3 and 4 compared with quartile 1 were 0.48 (95% CI, 0.31-0.74) and 0.41 (0.26-0.65), respectively.
A comparison of BMD in the highest and lowest quartiles of dietary copper intake indicated that the mean total femur BMD and mean total spine BMD in quartile 4 were 0.03 g/cm3 and 0.02 g/cm3 greater, respectively, than quartile 1.
Study limitations included the cross-sectional design and potential residual confounding.
“In conclusion, our results indicate that dietary and total copper intake was positively associated with increasing BMD in US adults and negative with the risk of osteoporosis in US adults,” the authors noted. “Furthermore, the results need to be confirmed with prospective data,” the researchers concluded.
Fan Y, Ni S, Zhang H. Associations of copper intake with bone mineral density and osteoporosis in adults: data from the National Health and Nutrition Examination Survey. Biol Trace Elem Res. Published online July 20, 2021. doi:10.1007/s12011-021-02845-5