Table 3.

Summary of the studies examining associations of maternal vitamin D status with offspring cognitive function

Author, Year, Sample size, Age, Country, Study design	Nutrient	Cognitive function	Results after adjustment for confounders	QS and RB
20Gale C; 2008  N = 178  Age 9 years  UK  Prospective longitudinal	Serum vitamin D concentrations assessed at 28-42 weeks gestation 21.2 % had <27.5 nmol/L 28.3 % had 27.5-50 nmol/L	Wechsler Abbreviated Scale of Intelligence Full-scale, verbal or performance IQ	No association between vitamin D concentrations and offspring IQ (full-scale, verbal or performance) Confounders adjusted for: Unadjusted	16 Medium
21Whitehouse AJO; 2012  Age 5 years (n = 534)  Age 10 years (n = 474)  Australia  Prospective longitudinal	Serum vitamin D concentrations assessed at 18 weeks gestation 25.2 % mothers had insufficiency (≤46 nmol/L) (lowest quartile)	Peabody Picture Vocabulary Test Receptive language	Children of mothers with vitamin D insufficiency (lowest quartile (≤46 nmol/L) were at increased risk (OR = 1.97) of language impairment compared to children of mothers without insufficiency (highest quartile (≥72 nmol/L; OR = 1.00) Confounders adjusted for: MA, MS, parity, family income, season of maternal blood sampling	13 Medium
22Morales E; 2012  N = 1820  Age 11-23 Months  Spain  Prospective population based  cohort study	Plasma vitamin D concentrations assessed during 12-23 weeks gestation 19.5 % mothers had deficiency (<20 ng/ml) 31.5 % had insufficiency (20-30 ng/ml)	Bayley Scales of Infant Development (mental (MDI) and psychomotor (PDI) developmental score)	A positive linear association between vitamin D concentrations and MDI and PDI Per 10 ng/ml increase in vitamin D concentrations MDI and PDI score increased by β = 0.79 and β = 0.88 points respectively Compared to infants of deficient mothers, infants of mothers with normal level scored higher MDI (β = 2.60) and PDI (β = 2.32) points respectively Confounders adjusted for: The child’s sex, BWT, area of study, maternal country of origin, MA, parity, pre-pregnancy BMI, SES, ME, MS, alcohol and season	15 Medium

QS quality score, RB risk of bias, MA maternal age, BWT birthweight, ME maternal education, MS maternal smoking, BMI body mass index, SES socio-economic status