To examine cross-sectional relationships between plasma vitamin D and cardiometabolic risk factors in young adults.

Data were collected from interviews, physical examinations and biomarker measurements. Total plasma 25-hydroxyvitamin D (25(OH)D) was measured using LC–tandem MS. Associations between 25(OH)D and cardiometabolic risk factors were modelled using weighted linear regression with robust estimates of standard errors.

Individuals born in Jerusalem during 1974–1976.

Participants of the Jerusalem Perinatal Study (n 1204) interviewed and examined at age 32 years. Participants were oversampled for low and high birth weight and for maternal pre-pregnancy obesity.

Mean total 25(OH)D concentration among participants was 21·7 (sd 8·9) ng/ml. Among males, 25(OH)D was associated with homeostatic model assessment of insulin resistance (natural log-transformed, β=−0·011, P=0·004) after adjustment for BMI. However, these associations were not present among females (P for sex interaction=0·005).

We found evidence for inverse associations of 25(OH)D with markers of insulin resistance among males, but not females, in a healthy, young adult Caucasian population. Prospective studies and studies conducted on other populations investigating sex-specific effects of vitamin D on cardiometabolic risk factors are warranted.