Relationship between lipids and bone mass in 2 cohorts of healthy women and men

A number of recent findings seem to indicate that fat and bone metabolism are strictly connected. We investigated the relationship between lipid profile and bone mineral density (BMD) in 236 either pre- or postmenopausal women, aged 35-81 years, attending our osteoporosis center ("clinic group"). In order to verify the consistency of the results, 265 men and 481 women aged 68-75, participating in a population-based epidemiological investigation ("community cohort"), were also studied. Lumbar spine, femoral neck, total hip and total body BMD, total body fat, % fat mass and lean mass were measured using dual energy X-ray absorptiometry (DXA). In the clinic group, lumbar spine and hip BMD Z score values were both strongly related to all measured serum lipids: the relationship was negative for HDL cholesterol (P < 0.05) and Apo A lipoprotein (P < 0.000) and positive for LDL cholesterol (P < 0.05), Apo B lipoprotein (P < 0.001) and triglycerides (P < 0.05). When BMD values were adjusted for body weight and BMI, most relationships remained statistically significant. In the community cohort, total body and hip BMD values were strongly related in both men and women to age, body weight, height, BMI, fat mass, lean mass, % fat mass. Total body and hip BMD were significantly related to serum lipids in both women and men. The relationship was negative for HDL cholesterol and positive for total cholesterol, triglycerides and LDL cholesterol. Most of these relationships (triglycerides, HDL cholesterol, LDL/HDL cholesterol ratio in women, and all measured lipids in men) remained statistically significant (P values ranging from 0.000 to 0.03) when the BMD values were adjusted also for anthropometric measures (body weight, height, fat mass). This study demonstrates for the first time that the lipid profile is strictly related to bone mass in both men and women. The interpretation of this association remains hypothetical but it might open new perspectives for understanding the mechanisms controlling bone metabolism.