Although the mean total intake of vitamin D among mothers met current Nordic recommendations, 71% of women and 15% of newborns were vitamin D deficient during the pregnancy. Our results suggest that maternal vitamin D status affects bone mineral accrual during the intrauterine period and influences bone size. More efforts should be made to revise current nutrition recommendations for pregnant women that may have permanent effects on the well-being of children.

IMPORTANCE Although guidelines for vitamin D supplementation in infants have been widely implemented, they are mostly based on studies focusing on prevention of rickets. The optimal dose for bone strength and infection prevention in healthy infants remains unclear. OBJECTIVE To determine whether daily supplementation with 1200 IU of vitamin D 3 increases bone strength or decreases incidence of infections in the first 2 years of life compared with a dosage of 400 IU/d. DESIGN, SETTING, AND PARTICIPANTS A randomized clinical trial involving a random sample of 975 healthy term infants at a maternity hospital in Helsinki, Finland. Study recruitment occurred between January 14, 2013, and June 9, 2014, and the last follow-up was May 30, 2016. Data analysis was by the intention-to-treat principle. INTERVENTIONS Randomization of 489 infants to daily oral vitamin D 3 supplementation of 400 IU and 486 infants to 1200 IU from age 2 weeks to 24 months. MAIN OUTCOMES AND MEASURES Primary outcomes were bone strength and incidence of parent-reported infections at 24 months. RESULTS Of the 975 infants who were randomized, 485 (49.7%) were girls and all were of Northern European ethnicity. Eight hundred twenty-three (84.4%) completed the 24-month follow-up. We found no differences between groups in bone strength measures, including bone mineral content (mean difference, 0.4 mg/mm; 95% CI, −0.8 to 1.6), mineral density (mean difference, 2.9 mg/cm 3 ; 95% CI, −8.3 to 14.2), cross-sectional area (mean difference,-0.9 mm 2 ; 95% CI, −5.0 to 3.2), or polar moment of inertia (mean difference,-66.0 mm 4 , 95% CI, −274.3 to 142.3). Incidence rates of parent-reported infections did not differ between groups (incidence rate ratio, 1.00; 95% CI, 0.93-1.06). At birth, 914 of 955 infants (95.7%) were vitamin D sufficient (ie, 25-hydroxyvitamin D [25(OH)D] concentration Ն20.03 ng/mL). At 24 months, mean 25(OH)D concentration was higher in the 1200-IU group than in the 400-IU group (mean difference, 12.50 ng/mL; 95% CI, 11.22-13.78). CONCLUSIONS AND RELEVANCE A vitamin D 3 supplemental dose of up to 1200 IU in infants did not lead to increased bone strength or to decreased infection incidence. Daily supplementation with 400 IU vitamin D 3 seems adequate in maintaining vitamin D sufficiency in children younger than 2 years.

Adiponectin is an adipocyte-derived hormone with profound insulin-sensitizing, antiinflammatory, and antiatherogenic effects. Apart from its obvious potential as a mediator of adult metabolic syndrome, adiponectin could have a significant role in regulating fetal growth.We measured plasma adiponectin concentrations by ELISA in cord vein of 197 infants. Of them, 122 were born preterm (gestational age, 22-32 wk), and 75 at term (49 from a healthy and 26 from a diabetic pregnancy, with similar findings, and thus all data from term infants pooled).Mean adiponectin concentrations increased from less than 1 microg/ml at 24 wk gestation to approximately 20 microg/ml at term. One week increase in gestational age corresponded in preterm infants to 43% increase (95% confidence interval 34-53%; P < 0.0001) in adiponectin and term infants to 21% increase (12-31%; P < 0.0001). In preterm infants, one unit increase in birth weight sd score corresponded to 42% increase (22-66%; P = 0.0001) in adiponectin, and females had 57% higher adiponectin concentrations (0-146%; P = 0.05) than males. These differences were not seen in term infants. Adiponectin levels were lower in preterm infants with recent (<12 h) exposure to maternal betamethasone but were unrelated to mode of delivery, preeclampsia, or impaired umbilical artery flow. In conclusion, adiponectin concentrations in fetal circulation show a 20-fold rise between 24 wk gestation and term and, in preterm infants are associated with birth weight sd score, sex, and glucocorticoid exposure. Adiponectin may play an important role in regulating fetal growth and explaining its links to the metabolic syndrome and its consequences during adult life.

Vitamin D3 supplementation with up to 40 μg/d from age 2 wk to 3 months was safe and caused no hypercalcemia or hypercalciuria. The 40-μg dose maintained S-25-OHD above 80 nmol/liter in all infants. More extensive and longer intervention studies are necessary to assess long-term effects.