The aim of the study is to obtain accurate estimates of prevalence of diabetes, impaired glucose tolerance and metabolic syndrome as well as related risk factors in the population. In total, 9000 women and men aged 18-75 years were selected randomly from the Population Registry and were invited to the study. Altogether 5208 (54.7% of those invited) took part in the baseline study in 2004-2008. Six years later, the participants were invited to the first follow-up examination in 2011-2015; nearly 4000 participated, of which 160 with incident diabetes. The second follow-up started in 2018 and all those alive who participated in the first examination are going to be invited.
The subjects participates in a 75 g OGTT after a 12 h overnight fast in order to find out the prevalence of diabetes and impaired glucose tolerance. Samples for insulin, diabetes related antibodies and blood lipids are drawn. In addition, samples are drawn for genetic analyses in order to study heritability of diabetes. Moreover, height, weight, waist circumference, blood pressure and fat percent are measured.
At the first visit, about 60% of participants (those who were eligible and willing) participated in 2 km walking test that assessed physical fitness. The participants also fill in questionnaires on family history of diabetes and life style factors such as smoking, alcohol consumption, nutrition and exercise. The participants also fill in questionnaires on presence of psychosocial stress and depression in order to study whether these are associated with the risk of diabetes.
Type 2 diabetes is a result of a collision between genetic inheritance and environmental factors. Some of the genetic factors behind diabetes are inherited differently from the father and mother. Often only gene from one parent (father or mother) is active and the other one is silent. In addition, some of the inherited genetic factors can be altered during the fetal period. In order to study these genetic features further, we have invited relatives (parents, children, spouses, siblings) of the original PPP-Botnia study participants to take part in the PPP-Botnia Trio study. The study started in 2016 and is ongoing.