Prevalence and incidence rate of diabetes mellitus in a Swedish community during 30 years of follow-up

Increasing diabetes prevalence has been reported in most European countries in the last 20 years. In this study we report on the development of prevalence and incidence of diabetes from 1972 to 2001 in Laxa, a rural community in central Sweden. A diabetes register was established at the primary healthcare centre (PHCC) in Laxa, beginning in 1972 and based on data from clinical records at the PHCC, nearby hospitals and private practitioners in the area. In addition, case-finding procedures involving 85% of the residents aged 35 to 79 years old was performed from 1983 onwards. During the study period a total of 776 new diabetes cases was found, 36 type 1 diabetes mellitus and 740 type 2 diabetes mellitus. The age-standardised incidence rates for type 1 diabetes mellitus and type 2 diabetes mellitus were 0.15 and 3.03 cases per 1,000 population, respectively. No increase in incidence over time was detected for either forms of diabetes. Age-standardised prevalence for women and men increased from 28.3 and 25.9, respectively, per 1,000 in 1972 to 45 and 46.3 per 1,000 in 1988 (p < 0.0001), thereafter falling to a mean of 43.5 per 1,000 for women, while men had a mean of 44.9 per 1,000 for the rest of the study period. The prevalence of diabetes mellitus in Laxa is high, but has not increased during the last 13 years. The incidence rate was relatively stable over the whole 30-year period.