Association between dietary folate intake and bone mineral density in a diverse population: a cross-sectional study

Abstract

Background: Osteoporosis is a major public health problem, yet the association between dietary folate intake and bone health has been rarely studied. This study aimed to investigate the relationship between dietary folate intake and bone mineral density (BMD) in the general population of the USA.

Methods: Utilizing data from the National Health and Nutrition Examination Survey, dietary folate intake was gauged through 24-h dietary recall and BMD was determined via dual-energy X-ray absorptiometry. Multivariate linear regression models and generalized additive models were employed for correlation analysis.

Results: The study incorporated 9839 participants (48.88% males, aged 20-85 years, mean age: 47.62 ± 16.22). The average dietary folate intake stood at 401.1 ± 207.9 μg/day. And the average total femur, femoral neck, trochanter, intertrochanter, and lumbar BMD were 0.98 ± 0.16 g/cm², 0.84 ± 0.15 g/cm², 0.73 ± 0.13 g/cm², 1.16 ± 0.19 g/cm², and 1.03 ± 0.15 g/cm², respectively. The higher quartiles of dietary folate intake directly correlated with increased total femoral, femoral neck, intertrochanteric, and lumbar BMD (P for trend = 0.003, 0.016, < 0.001, and 0.033, respectively). A consistent positive association between folate intake and BMD across age groups was observed, with significant findings for individuals over 80 years and non-Hispanic whites. Physical activity level and serum 25-hydroxyvitamin D levels influenced the association, with an optimal daily folate intake of 528-569 µg recommended for postmenopausal women.

Conclusion: In summary, our study reveals a significant positive association between dietary folate intake and BMD, across different age groups and particularly among individuals over 80 years old. Non-Hispanic whites benefit the most from increased folate intake. Physical activity level and serum 25-hydroxyvitamin D levels interact with this association. Screening and early intervention for osteoporosis may be essential for individuals with low dietary folate intake.

Keywords: Bone mineral density; Cross-sectional; Dietary folate intake; Nonlinear relationship.

Fig. 1

Flowchart of participant selection

Fig. 2

Relationship between dietary folate intake and BMD in postmenopausal women (A), premenopausal women (B) and men (C), 1 total femur, 2 femoral neck, 3 intertrochanter, 4 trochanter, 5 lumbar spine. The number of postmenopausal women = 2293; premenopausal women = 2516; men = 5030. Solid red line represents the smooth curve fit between variables according to GAM. Blue bands represent the 95% of confidence interval from the fit. Y-axis represents BMD content, and x-axis represents dietary folate intake. Models were adjusted for age, race, PIR, marital status, BMI, hypertension, serum cotinine, alcohol drinking status, PA, and 25(OH)D

Fig. 3

Relationship between dietary folate intake and BMD in different ages, A total femur, B femoral neck, C intertrochanter, D trochanter, E lumbar spine. The red line represents 20–39 years old; the green line represents 40–59 years old; the blue line represents 59–79 years old; and the purple line represents greater than or equal to 80 years old. Y-axis represents BMD content, and x-axis represents dietary folate intake. Models were adjusted for age, gender, race, PIR, marital status, BMI, hypertension, serum cotinine, alcohol drinking status, PA, and serum 25(OH)D

Fig. 4

Relationship between dietary folate intake and BMD in different races, A total femur, B femoral neck, C intertrochanteric, D trochanter, E lumbar spine. The red line represents Mexican American, the yellow line represents other Hispanic, the green line represents non-Hispanic white, the blue line represents non-Hispanic black, and the purple line represents Other Race—Including Multi-Racial. Y-axis represents BMD content, and x-axis represents dietary folate intake. Models were adjusted for age, gender, PIR, marital status, BMI, hypertension, serum cotinine, alcohol drinking status, PA, and serum 25(OH)D

Fig. 5

Relationship between dietary folate intake and BMD in people with different PA levels, A total femur, B femoral neck, C intertrochanter, D trochanter, E lumbar spine. The red line represents VLPA, the green line represents LPA, the blue line represents MPA, and the purple line represents HPA. Y-axis represents BMD content, and x-axis represents dietary folate intake. Models were adjusted for age, gender, race, PIR, marital status, BMI, hypertension, serum cotinine, alcohol drinking status, PA, and serum 25(OH)D

Fig. 6

Relationship between dietary folate intake and BMD in people with different serum 25(OH)D, A total femur, B femoral neck, C intertrochanter, D trochanter, E lumbar spine. The red line represents 25(OH)D levels greater than 76.5 nmol/L, the green line represents between 25(OH)D levels 60.4 and 76.5 nmol/L, the blue line represents 25(OH)D levels between 44.7 and 60.4 nmol/L, and the purple line represents 25(OH)D levels less than 44.7 nmol/L. Y-axis represents BMD content, and x-axis represents dietary folate intake. Models were adjusted for age, gender, race, PIR, marital status, BMI, hypertension, serum cotinine, alcohol drinking status, PA, and serum 25(OH)D