Genetics of biological aging in Mennonites of Midwestern United States

Biological aging was assessed in three Mennonite communities of Kansas and Nebraska through the use of a number of complex phenotypes: 6 neuromuscular, 2 pulmonary, 2 physiological, 35 anthropometric parameters plus 25 blood chemicals. More than 1200 volunteers from Goessel and Meridian, Kansas, and Henderson, Nebraska, participated in various phases of this project, initiated in 1980 and continued until the present time. A linear or curvilinear decline in neuromuscular and pulmonary performance was observed as a function of age, beginning at 50 years and declining rapidly until death. The individual transmissibilities (combined genetic and cultural transmission between parents and offspring) for each variable are relatively low (0.001 – 0.662) for neuromuscular and pulmonary performances. However, the reconstitution of families followed by stepwise multiple regression analysis of a large assortment of traits, yielded relatively high and significant heritabilities (additive genetic variance/total phenotypic variance) for differential biological aging. Variance decomposition methods were used to measure biological aging characterized by the residuals of a stepwise multiple regression of traits on chronological age. This analysis yielded a heritability estimate for differential biological aging of 0.43 ± 0.16 in the Goessel sample. Individual residual values were used to define early or late aging individuals. A follow up of the mortality patterns of those Mennonites who participated in the study 20 years prior to the analyses revealed that males who aged faster than predicted by multiple regression analysis died sooner than did males who aged