Birthweight has implications for physical and mental health in later life. Using data from Caucasian twins collected in Australia, the Netherlands and the United States, and from East Asian twins collected in Japan and South Korea, we compared the total phenotypic, genetic and environmental variances of birthweight between Caucasians and East Asians. Model-fitting analyses yielded four major findings. First, for both males and females, the total phenotypic variances of birthweight were about 45% larger in Caucasians than in East Asians. The larger phenotypic variances were mainly attributable to a greater shared environmental variance of birth- weight in Caucasians (ranging from 62% to 67% of variance) than Asians (48% to 53%). Second, the genetic variance of birthweight was equal in Caucasians and East Asians for both males and females, explaining a maximum of 17% of variance. Third, small variations in total phenotypic variances of birthweight within Caucasians and within East Asians were mainly due to differences in nonshared environmental variances. We speculate that maternal effects (both genetic and environmental) explain the large shared environmental variance in birthweight and may account for the differences in phenotypic variance in birthweight between Caucasians and East Asians. Recent molecular findings and specific environmental factors that are subsumed by maternal effects are discussed.

The design of daily-life products that can be used in a safe and comfortable way by many consumers requires ergonomic data concerning these users. With regard to the elderly, hardly any ergonomic data were available.In this study, measurements were done on about 79 physical, psychomotor, sensory and cognitive variables. The sample consisted of 750 persons: 123 in the age between 20 and 30 years and 623 aged 50 years and over.The results reveal different patterns of level and variation with age. Generally speaking, the physical data exhibit a relatively small variation with age; in other words, the variation within age groups is much larger. For the psychomotor and sensory variables variance generally increased with age. Especially after the age of 65 or 70 the level of performance decreased compared to that of younger subjects.As far as differences between the sexes are concerned, it is concluded that there are marked differences in the physical variables between males and females. Body build and the amount of force exerted differ. The psychomotor variables also show systematic differences between men and women. For the sensory and cognitive variables, few systematic differences between the sexes were found.People with capacities in the lower percentiles of the frequency distribution appear to have difficulties in performing daily-life activities. However, they still manage to live independently. This is possible because they use all kinds of solutions to compensate for the lower level of ability.

The Acknowledgement was inadvertently omitted from the original publication of this article. The text should read as given below: