Plasma fatty acid composition predicts bone mineral accrual from childhood to adolescence: the Physical Activity and Nutrition in Children study

Little is known about the associations of plasma fatty acids (FAs) with bone mineral accrual, and the evidence is mostly based on cross-sectional data. In this observational study, we investigated for the first time the longitudinal associations of plasma FA composition as well as desaturase and elongase enzyme activities with BMD from childhood to adolescence. Altogether, 480 children (227 girls) aged 7-9 yr attending baseline examinations were included in the current analyses. The longitudinal associations of the proportions of FAs in plasma phospholipids, analyzed by gas chromatography, as well as estimated desaturase and elongase activities with total body less head BMD, measured by dual-energy X-ray absorptiometry, were analyzed by linear mixed-effects models using values from baseline, 2-yr, and 8-yr follow-up and adjusted for sex, maturity offset, follow-up time, and lean mass (LM) or fat mass (FM). Decreased proportion of linoleic acid (standardized regression coefficient β = -.023, p = .001), increased proportion of dihomo-gamma-linolenic acid (β = .029, p < .001), and Δ6-desaturase activity (β = .032, p < .001) were associated with increased BMD independent of sex, maturity offset, follow-up time, LM, and FM. Increased proportions of nervonic acid (β = .018, p = .012), arachidonic acid (β = .019, p = .017), and docosapentaenoic acid (β = .020, p = .013) were associated with increased BMD, and these associations were partly explained by LM. Increased proportions of arachidic acid (β = .022, p = .005), behenic acid (β = .018, p = .010), lignoceric acid (β = .015, p = .040), and palmitoleic acid (β = .016, p = .013), increased stearoyl-CoA-desaturase activity (β = .017, p = .009), and decreased elongase activity (β = -.017, p = .023) were associated with increased BMD, and these associations were partly explained by FM. Single plasma saturated, monounsaturated, and polyunsaturated FAs have divergent longitudinal associations with BMD from childhood to adolescence. Plasma FA composition predicts bone mineral accrual from childhood to adolescence, implying that FA metabolism is important for healthy bone development since childhood.