MedWire News: Plasma phosphatidylcholine (PC) essential fatty acids have opposing effects on bone mineral density (BMD) and fracture risk in men and women, a study by US researchers indicates.
These gender-specific effects warrant further investigation, say Katherine Tucker (Northeastern University, Boston, Massachusetts) and fellow authors writing in the Journal of Bone and Mineral Research.
Tucker and co-workers examined associations between polyunsaturated fatty acids (PUFA), BMD at the femoral neck, and hip fracture risk, among participants in the Framingham Osteoporosis Study.
This was an ancillary study to the Framingham Heart Study that included 1164 surviving members of the original cohort who underwent BMD assessment at the 20th biennial examination.
A subset of 829 participants also had plasma PC PUFAs measured, 556 individuals had BMD re-assessed 4 years later, and 765 individuals were followed-up for incident hip fracture over 17 years.
The study yielded three novel and unexpected findings, say Tucker et al. First, higher baseline levels of plasma PC docosahexaenoic acid (DHA) were significantly correlated with accelerated BMD loss in women but with slower BMD loss in men.
Second, higher baseline levels of plasma PC linoleic acid (LOA) were significantly correlated with lower baseline BMD in women, and with an increased risk for hip fracture in both men and women during follow-up.
The association between plasma PC linoleic acid and fracture risk became non-significant after adjusting for body mass index, however.
Third, higher baseline levels of plasma PC arachidonic acid (AA) were significantly correlated with higher baseline BMD in men, and with a significantly reduced 17-year risk for hip fracture in both men and women.
Tucker et al write: "Taken together, these results suggest protective effects of plasma PC AA on femoral neck BMD in men, in addition to protective effects of plasma PC AA on hip fracture risk in women and men.
"Our results also suggest that detrimental effects of plasma PC LA on BMD or hip fracture risk may be confounded by BMI. The differential effect of plasma PC DHA on BMD in elderly women and men observed in our study needs further clarification."
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