Figure 1.

The association between serum testosterone levels and lumbar bone mineral density. (a) Each black point represents a sample. (b) Solid red line represents the smooth curve fit between variables. Blue bands represent the 95% confidence interval from the fit. Age, race, body mass index, education level, income-to-poverty ratio, smoking status, drinking behavior, moderate activities, calcium supplement use, blood urea nitrogen, serum uric acid, total protein, serum estradiol level, serum phosphorus, and serum calcium were adjusted.