To investigate the association between the intake of n-6 PUFA and subsequent change in body weight and waist circumference at different levels of the carbohydrate:protein ratio.

Follow-up study with anthropometric measurements at recruitment and on average 5·3 years later. Dietary intake was determined at recruitment by using an FFQ that was designed for the study and validated. We applied linear regression models with 5-year change in weight or waist circumference as outcome and including a two-way interaction term between n-6 PUFA and carbohydrate intakes, lower-order terms, protein intake, long-chain n-3 PUFA intake and other potential confounders. Due to adjustment for intake of protein, levels of carbohydrate indirectly reflect levels of the carbohydrate:protein ratio.

Diet, Cancer and Health follow-up study, Denmark.

Women and men (n 29 152) aged 55 years.

For a high intake of n-6 PUFA (6·9 % of energy) v. a low intake of n-6 PUFA (3·4 % of energy), the difference in 5-year weight change was −189·7 g (95 % CI −636·8, 257·4 g) at a low carbohydrate:protein ratio and −86·7 g (95 % CI −502·9, 329·6 g) at a high carbohydrate:protein ratio; the differences in 5-year waist circumference change were 0·26 cm (95 % CI −0·47, 0·98 cm) and −0·52 cm (95 % CI −1·19, 0·15 cm), respectively. Inclusion of the dietary glycaemic index did not change the results.

No consistent associations between the intake of n-6 PUFA and change in body weight or waist circumference at different levels of the carbohydrate:protein ratio were observed.

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.