Table 4.

Mean growth rates per linear spline period in the non-manual social class and the mean difference in growth rates comparing the manual with the non-manual social class

	Mean growth rate (SD) non-manual social class	Mean difference (95% CI) manual vs. non-manual social class
Birth length, cm Growth rate, cm/month	50.173 (1.642)	−0.439 (−0.599 to −0.279)
0–3 months	3.553 (0.241)	0.087 (0.016 to 0.158)
3–12 months	1.626 (0.136)	−0.002 (−0.030 to 0.026)
1–3 years	0.836 (0.071)	−0.015 (−0.026 to −0.005)
3–10 years	0.531 (0.035)	−0.008 (−0.013 to −0.003)