Fig. 2. Interaction between calcium and caffeine intake on bone mineral density (BMD) of femoral neck and trochanter. Values, mean ± SE (g/cm²), are adjusted for below and above median of calcium intake (750 mg/day), caffeine consumers and non-consumers, and all other confounders. *Neck BMD in <750 mg/day Ca/caffeine consumers: p = 0.03, vs. <750 mg/day Ca/caffeine non-consumers; p = 0.02, vs. >750 mg/day Ca/caffeine non-consumers; p = 0.05, vs. >750 mg/day Ca/caffeine consumers. **Trochanter BMD in <750 mg/day Ca/caffeine consumers: p = 0.04, vs. <750 mg/day Ca/caffeine non-consumers; p = 0.05, vs. >750 mg/day Ca/caffeine non-consumers; p = 0.01, vs. >750 mg/day Ca/caffeine consumers. Note the negative effect of caffeine in the <750 mg/day Ca group and no effect in the >750 mg/day Ca group.