Dietary choline intake is directly associated with bone mineral density in the Hordaland Health Study

Abstract

Background: Choline is an important nutrient either obtained from a variety of foods or synthesized endogenously, and it is the precursor of betaine. We previously reported positive associations between plasma free choline and bone mineral density (BMD). Animal studies suggest an impact of dietary choline on bone metabolism, but the role of dietary intake of choline and betaine for human bone health is unknown. Objectives: The main aims were to examine the associations of dietary choline, choline species, and betaine with BMD and to study the relations between dietary and plasma free choline and betaine. Methods: Study subjects were participants in the Hordaland Health Study, including 2649 women and 1983 men (aged 46-49 or 71-74 y). BMD was measured by dual-energy X-ray absorptiometry, and dietary intake was obtained by using a validated 169-item food-frequency questionnaire. Risk associations were assessed by logistic regression and correlations by r (Spearman's bivariate rank order correlation). Results: Subjects in the lowest compared with the highest tertile of dietary total choline, free choline, glycerophosphocholine, phosphocholine, phosphatidylcholine, and sphingomyelin had a higher risk of low-femoral neck BMD, defined as the lowest BMD quintile. Particularly strong associations were found among middle-aged men for intake of free choline (OR: 1.83; 95% CI: 1.24, 2.69; P = 0.002) and glycerophosphocholine (OR: 2.13; 95% CI: 1.43, 3.16; P < 0.001) and among elderly women for total choline (OR: 1.96; 95% CI: 1.33, 2.88; P = 0.001) and phosphatidylcholine (OR: 1.94; 95% CI: 1.33, 2.84: P = 0.001) intake. No significant associations were observed between dietary betaine and BMD. Dietary total choline, free choline, glycerophosphocholine, phosphatidylcholine, and sphingomyelin correlated weakly with plasma free choline (r: 0.07, 0.05, 0.07, 0.07, and 0.05, respectively; P < 0.01). Dietary betaine correlated with plasma betaine (r: 0.23; P < 0.001). Conclusion: Dietary choline was positively associated with BMD in middle-aged and elderly participants.