Increased Serum Total and Free 25-Hydroxyvitamin D with Daily Intake of Cholecalciferol-Fortified Skim Milk: A Randomized Controlled Trial in Colombian Adolescents.

BACKGROUND: The efficacy of cholecalciferol (vitamin D3) food fortification in low- and middle-income countries near the Equator is unknown. OBJECTIVES: We examined the effects of providing cholecalciferol-fortified skim milk to adolescents and their mothers on serum total 25(OH)D, free 25(OH)D, and vitamin D-binding protein (DBP) concentrations in a randomized controlled trial. METHODS: We randomly assigned 80 Colombian families each with a child aged 12-14.5 y and their mother 1 L of skim milk daily, either fortified with 2400 IU (60 µg) cholecalciferol or unfortified, for 6 wk. We prescribed 500 mL of milk daily to adolescents; mothers consumed the remainder ad libitum. We estimated intent-to-treat effects as the between-arm difference in the change in serum total and free 25(OH)D and DBP concentrations from baseline to the end of follow-up. Secondary analyses included stratification by baseline characteristics and per-protocol comparisons. RESULTS: Among adolescents, fortification effects (95% CI) on serum total 25(OH)D, free 25(OH)D, and DBP concentrations were 5.4 nmol/L (2.1, 8.8 nmol/L), 0.6 pmol/L (-0.2, 1.4 pmol/L), and -416 nmol/L (-944, 112 nmol/L), respectively. Effects on total 25(OH)D were stronger in adolescents with lower DBP concentrations, darker skin, less sunlight exposure, and higher compliance than in their respective counterparts. Fortification increased free 25(OH)D concentrations in high compliers. Among mothers, the effects (95% CI) on total 25(OH)D and DBP concentrations were 4.0 nmol/L (0.6, 7.5 nmol/L) and -128 nmol/L (-637, 381 nmol/L), respectively. There were no adverse events. CONCLUSIONS: Provision of cholecalciferol-fortified skim milk increases serum total 25(OH)D concentrations in Colombian adolescents and adult women.

Validity of maternal birthweight recall among Colombian children.

Low birthweight and preterm birth are associated with adverse health outcomes later in life, but acquisition of accurate birthweight information is not always feasible in large epidemiological studies. We examined the validity of child birthweight and gestational age recall by mothers, and the extent to which recall bias affects associations between birthweight and childhood obesity in children from Bogotá, Colombia. We surveyed mothers of 3,202 schoolchildren aged 5-12 years about child's weight and gestational age at birth, and sociodemographic characteristics. In a subsample of 279 children, we obtained hospital birth records and extracted birthweight, gestational age, and other perinatal information. Mean birthweight (SD) was 3,106 (739) grams according to maternal recall and 2,977 (462) grams according to hospital records (difference 129 g; 95% CI = 55, 203). Thirty-three percent of mothers recalled their children's birthweights exactly as they appeared in hospital records. Mother's age and fewer years of education were each significantly associated with greater birthweight recall bias. Specificity of low birthweight (<2,500 g) and preterm birth (<37 weeks gestation) from maternal recall was 0.95 and 0.86, respectively; however, sensitivity was lower (0.66 and 0.67, respectively). Associations between recalled birthweight and BMI-for-age or overweight during school age were weaker than those with hospital record birthweight. Maternal birthweight recall 5-12 years after birth differs from hospital record birthweight by a clinically meaningful amount. Birthweight recall should be used with caution in epidemiological studies conducted in this and comparable settings. Associations between birthweight and obesity may be stronger than they appear when using recalled birthweight.