Individuals still living in northern Finland or the Helsinki area at 31 y were invited to a clinical examination (n = 6,007 attended). Anthropometric measurements, samples for biochemical assays and for DNA extraction and genotyping (n = 5,753) were collected (Figure 2). Informed consent for the use of the data including DNA was obtained from all subjects. The present study was approved by ethics committees in Oulu and Oxford universities in accordance with the Declaration of Helsinki.
