Lack of Influence of Calcium/Phosphorus Ratio on Hip and Lumbar Bone Mineral Density in Older Americans: NHANES 2005-2006 Cross-Sectional Data

OBJECTIVES: We sought to ascertain the effect of a low dietary calcium/phosphorus (Ca:P) ratio on the bone health of older adults in the United States. The present analysis assessed whether a high dietary consumption of P, which generally leads to a low dietary Ca:P ratio, has an unfavorable effect on the bone mineral density (BMD) of the hip and lumbar vertebrae in a representative sample of older US men and women. DESIGN: For the 1228 men and women aged 50 to 70 and ≥71 years included in the National Health and Nutrition Examination Survey (NHANES) 2005 to 2006 cycle, quintiles of the dietary Ca:P ratio were tested for their association with hip and lumbar BMD after adjusting for body mass index (BMI). All data in this observational study were cross-sectional. RESULTS: Women typically have higher dietary Ca:P ratios than men and lower BMDs. No trend emerged for any age or sex group when studying the relationship between the dietary Ca:P ratio and BMD with adjustment for BMI. CONCLUSIONS: A wide range of dietary Ca:P ratios in the diets of a cross-section of older adult men and women in the United States had little effect on the BMD of the hip (proximal femur) or the lumbar vertebrae (spine), even among those consuming large amounts of Ca supplements. Despite the lack of complete assessment of total P intake in the United States, these results suggest that high P consumption patterns and low dietary Ca:P ratios do not exert an adverse effect on BMD at major fracture sites in older adults.