Patterns and Correlates of Concurrent Serum Vitamin D, Folate, and Vitamin B₁₂ Status in a Rural Chinese Population

Vitamin D, folate, and vitamin B₁₂ are essential micronutrients with widespread insufficiencies globally. Although most previous research examined each of these nutrients individually, few studies have measured biomarkers of these nutrients concurrently in a large population.

We aimed to investigate the patterns of concurrent insufficiencies or deficiencies of these nutrients based on serum biomarkers and influencing factors in a rural Chinese population.

We analyzed the data from the nutrition biomarker substudy within the China Precision Nutrition and Health KAP Real World Study. Participants' nutrient status for vitamin D, folate, and vitamin B₁₂ was defined by serum biomarkers and grouped by the number of nutrients' insufficiency or deficiency (none, 1, 2, or all 3). Multiple logistic regression models identified factors associated with individual and combined nutrient insufficiencies or deficiencies.

Of 40,716 participants (37.5% male), 99% had ≥ 1-nutrient insufficiency or deficiency, 53.4% had 2, and 31.7% had all 3. The prevalence of 3-nutrient insufficiency or deficiency was highest in males aged <65 y (35.4%) and lowest in females aged <65 y (28.4%). The methylenetetrahydrofolate reductase TT genotype was associated with folate deficiency in both males and females. Current smoking was associated with folate deficiency and vitamin B₁₂ insufficiency in both sexes, with a more pronounced association observed in females. Additionally, higher body mass index was associated with vitamin D insufficiency and deficiency, particularly among males.

In this large rural Chinese population, concurrent vitamin D, folate, and vitamin B₁₂ insufficiencies/deficiencies were highly prevalent and varied by individual demographic, genetic, and lifestyle factors. The methodology and insights have implications for advancing precision nutrition, especially in underrepresented and understudied populations. This trial was registered at ChiCTR.org.cn as ChiCTR2100051983.