Objective: To evaluate levels of vitamin D3 and HDL-cholesterol (HDL-C), and the ratio of HDL-C to LDL-cholesterol (LDL-C), in schoolchildren receiving vitamin-D-fortified, fat-depleted, high-Ca milk in schools.

Design: Cross-sectional study of previously randomised schools receiving supplemental milk, compared with a matched control group.

Setting: Low-decile Year 1-6 schools in the Waikato region of New Zealand.

Subjects: Year 3 children from either milk schools or control schools, consenting to blood sampling.

Results: For eighty-nine children receiving supplementary daily milk, vitamin D3 levels were significantly higher than in eighty-three control children matched for age, sex, body composition and ethnicity (mean (sd): 49.6 (15.8) v. 43.8 (14.7) nmol/l, P = 0.011), as were HDL-C levels (mean (sd): 1.47 (0.35) v. 1.35 (0.29) mmol/l, P = 0.024) and HDL-C:LDL-C (median: 0.79 v. 0.71, P = 0.026). LDL-C levels were similar in both groups (mean (sd): 2.07 (0.55) v. 2.16 (0.60) mmol/l, P = 0.31). Of control children, 32/83 (20.2 %) of the milk group (Pearson's chi2 = 7.00, P = 0.008). Mean 25-hydroxyvitamin D (vitamin D3) levels in the milk group were still below the lower end of the recommended normal range (60 nmol/l).

Conclusions: Vitamin D3 levels are low in low-decile Year 3 children in midwinter. Levels are improved with vitamin-D-fortified milk but still below the recommended range. HDL-C and HDL-C:LDL-C levels are improved in the milk-supplemented group. This supports the supply of vitamin-D-fortified, fat-reduced milk to schools.