Height, weight and fertility among the participants of the Third Harvard Growth Study.

Abstract

The relationship between weight height weight/height and fertility was examined in 610 females and 621 males from a 1968 follow-up study of the Third Harvard Growth Study participants. The objective of the Third Harvard Growth Study was to measure longitudinally the physical and intellectual growth of normal children. Initiated in 1922 the project studied all children in 3 Boston area school districts from the time they entered school in the 1st grade until they either graduated moved or dropped out of school. Many anthropometric measurements and intelligence tests were taken on these children through the years. The number of students with 11 or more complete years of measurement was 1225. Partial data are available on other children making a total of approximately 4000. In 1968 a follow-up study was conducted on 1533 individuals most of whom were then approximately 50-55 years old. Data were collected via a mailed questionnaire and through examining vital statistics and reunion records for those either deceased or not responding to the questionnarie. Weight height and fertility were self reported by informants during the 1968 follow-up and were also available for many of them as children. The correlation between reported and actual weight was very high ranging from .90-.97. As the goal of the research was to examine the relationship between physique and fertility not at size per se the data was not biased for the study purposes. Males who reproduced were somewhat shorter and heavier than nonreproducing males but the means for height and weight were not significantly different. Nonreproducing males were significantly more variable in height although no significant differences in the variance of weight or weight/height were shown. In males only weight/height was significantly related to fertility. Weight and height were not. Reproducing females were significantly taller and heavier than nonreproducing women. Nonreproducing feamles were significantly more variable than reproducing females in weight/height. Height was unrelated to fertility but weight and weight/height were significantly related. As was the case with the male data the transformed weight and height variables did not show significant relationships with fertility. It is concluded that the relationship between weight and fertility is linear and positive. The tendency for heavy and heavy for height females to have large families held across ethnic and income groups and was not just a result of ethnicity or income.