Table 2. Association between mid-gestation and cord 25OHD deficiency and clinical autism case–control status.

	n	OR (95% CI)	χ2(1)	P
Maternal serum, mid-gestation: deficient v. sufficient	2770	2.42 (1.09–5.07)	4.64	0.03*
Maternal serum, mid-gestation: insufficient v. sufficient	3103	0.86 (0.43–1.62)	0.21	0.64
Cord blood, at birth: deficient v. sufficient	1673	0.94 (0.36–2.42)	0.02	0.90
Cord blood, at birth: insufficient v. sufficient	1761	1.25 (0.61–2.69)	0.37	0.54

^*Significant at alpha of 0.05.

25OHD, 25-hydroxyvitamin D.

^aEstimates are based on general linear model; a Firth correction was applied to the model.

^bCovariates included in the model are ethnicity of child, gender of child, birth weight of child, gestational age at time of birth, age of mother at intake, age of father at intake, smoking history of mother during pregnancy, educational level of mother and body mass index of mother at mid-gestation.

^cDeficient is 25OHD concentrations <25 nmol/L, insufficient is 25OHD concentrations from 25 to <50 nmol/L, sufficient is 25OHD concentrations ≥50 nmol/L.