Table 2.

Differences in birth size parameters for a 90% increase in maternal delivery intact PTH (iPTH) or 73% increase in maternal whole PTH (wPTH) concentrations among mother–infant pairs from a birth cohort in Dhaka, Bangladesh.

	Unadjusted models				Multivariable modela
	n	Difference in size/RRb	95% CI	Pc	n	Difference in size/RRb	95% CI	Pc
iPTH
LAZ	530	0.091	0.020, 0.161	0.012	487	0.064	−0.011, 0.139	0.09
WAZ	535	0.070	0.010, 0.129	0.022	490	0.056	−0.007, 0.118	0.08
HCAZ	534	0.082	0.015, 0.149	0.017	489	0.047	−0.027, 0.121	0.21
RKL	532	0.004	−0.050, 0.058	0.89	487	−0.004	−0.062, 0.053	0.88
SGA	535	0.92	0.85, 0.99	0.023	490	0.94	0.87, 1.02	0.17
wPTH
LAZ	486	0.033	−0.033, 0.099	0.32	479	0.018	−0.048, 0.084	0.60
WAZ	490	0.070	0.014, 0.125	0.014	482	0.057	0.003, 0.112	0.040
HCAZ	489	0.089	0.028, 0.151	0.004	481	0.061	−0.003, 0.125	0.06
RKL	487	−0.014	−0.064, 0.036	0.59	479	−0.012	−0.062, 0.038	0.64
SGA	490	0.91	0.85, 0.97	0.004	482	0.92	0.86, 0.99	0.024

^aMultivariable linear or Poisson regression models with robust error variance adjusted for: maternal log PTH, maternal magnesium, maternal log FGF23, maternal log CRP, vitamin D supplementation group, relative protein intake, maternal age, maternal height, maternal education, gravidity, gestational age at birth and season of birth. For models where RKL was the outcome, we additionally adjusted for sex. ^bDifference in size presented for LAZ, WAZ, HCAZ, and RKL. Relative risk presented for SGA. Effect sizes are for a 90 and 73% increase in iPTH and wPTH concentrations, respectively, which reflects a large but plausible difference in PTH concentrations corresponding to the observed effect of high dose vitamin D supplementation (28,000 IU/week) on PTH, vs placebo. ^cP < 0.05 considered significant.

HCAZ, head circumference-for-gestational age z-scores; LAZ, length-for-gestational age z-scores; RKL, rump-to-knee length; SGA, small-for-gestational age; WAZ, weight-for-gestational age z-scores.