Factors influencing the height of seven year old children--results from the National Child Development Study.

Abstract

Measurement was taken of the heights of the children between 7 and 8 years of age in the National Child Development Study (all children born in England Scotland and Wales during the week of 3-9 March 1958). Information was also obtained on the social class of the childs father the age and height of the childs mother her smoking habits during pregnancy the parity birthweight and length of gestation of the child and the number of younger siblings. The association of these with height have been analyzed both singly and jointly in all instances making allowance for the age and sex of the child. The present data provide no evidence of statistical interactions between sex and any of these variables; thus for example the height differences between social classes are the same for both boys and girls. After allowing for the other variables social class 1 or 2 children are 1.3 centimeters taller than children from social class 5. After allowing for the other variables 1st born children are on the average 2.3 centimeters taller than 4th or later born children. Birthweight and length of gestation are both associated with height at 7 centimeters. Children born before the 38th week of gestation are on average 1.1 centimeter shorter than those born between 38 and 42 weeks. After allowing for the other variables the children of mothers who smoked 10 or more cigarettes a day after the 4th month of pregnancy are on average about 1.0 centimeter shorter at age 7 than the children of mothers who did not smoke.