A team of researchers has described an association between reduced bone density in the lumbar spine and high total cholesterol in a paper published in Aging.
Previous studies were conflicting
In various populations, conflicting evidence has been found regarding a relationship between cholesterol and bone density. One study found that high HDL cholesterol was associated with higher bone density in post-menopausal women [1], another study found that there was no such relationship in South Korean women [2], but more studies [3, 4] found that there was a negative relationship in larger populations.
Making firm conclusions with a broad population
In an attempt to settle the issue with broad data, these researchers chose the large-scale National Health and Nutrition Examination Survey (NHANES). This data had been collected between 1999 and 2006. In an effort to avoid conflicting factors, the researchers specifically chose participants who were at least 60 years old and had neither cardiovascular disease nor cancer. There were a total of 3,290 people included, and approximately half of them were over the age of 70.
While there was only approximately a 6% difference, the high number of people involved in this study showed a very significant association between high total cholesterol and low bone density in the lumbar spine. There were several other factors associated with high total cholesterol. On average, people with low total cholesterol had slightly higher incomes, more blood urea nitrogen and uric acid, less protein in the blood, more serum calcium, and, interestingly, slightly higher BMIs.
Some of these variables had other associations. People with low protein concentrations had a somewhat nonlinear relationship between high total cholesterol and low bone density, and there was a much stronger relationship in people who had low serum calcium. In general, people with lower BMIs had less dense bones at all cholesterol levels.
Conclusion
While the researchers offer a few hypotheses for a potential causal connection, such as an increase in bone turnover, this is an association study that does not prove any sort of causal relationship. It is possible that other factors are the cause of both higher total cholesterol and less bone density. However, it does provide physicians with potential areas of interest when looking at blood biomarkers, and it also suggests potential study directions to researchers.
Literature
[1] Zolfaroli, I., Ortiz, E., García-Pérez, M. Á., Hidalgo-Mora, J. J., Tarín, J. J., & Cano, A. (2021). Positive association of high-density lipoprotein cholesterol with lumbar and femoral neck bone mineral density in postmenopausal women. Maturitas, 147, 41-46.
[2] Cui, L. H., Shin, M. H., Chung, E. K., Lee, Y. H., Kweon, S. S., Park, K. S., & Choi, J. S. (2005). Association between bone mineral densities and serum lipid profiles of pre-and post-menopausal rural women in South Korea. Osteoporosis International, 16, 1975-1981.
[3] Tang, Y., Wang, S., Yi, Q., Xia, Y., & Geng, B. (2021). High-density lipoprotein cholesterol is negatively correlated with bone mineral density and has potential predictive value for bone loss. Lipids in health and disease, 20(1), 1-17.
[4] Makovey, J., Chen, J. S., Hayward, C., Williams, F. M., & Sambrook, P. N. (2009). Association between serum cholesterol and bone mineral density. Bone, 44(2), 208-213.
