PATH-ANALYSIS OF FAMILY RESEMBLANCE WITH TEMPORAL TRENDS - APPLICATIONS TO HEIGHT, WEIGHT, AND QUETELET INDEX IN NORTHEASTERN BRAZIL

  • 1 January 1985
    • journal article
    • research article
    • Vol. 37  (1) , 178-192
Abstract
A multifactorial model incorporating temporal trends in its parameters is discussed. The model is a generalization of the .tau. model of Rice et al. in which the parameters are assumed to be specific functions of time. A special case of this model is fit to data on height, weight and Quetelet index in 1067 nuclear families to demonstrate the utility of the approach. There is evidently considerable temporal variation in family resemblance over time for all 3 traits. For height and Quetelet index, both the transmissibility, comparable to heritability, and residual sibling environmental correlation show temporal changes, while for weight, only the latter exhibits significant trends. Trends were not found in the marital correlation for any of the traits, and only limited evidence was found for trends in the maternal transmission parameter for height. This provides an objective method for evaluating the nature and sources of temporal trends in family resemblance, which can easily be incorporated into the framework of any model-based approach.