Methods A probability sample of a non-institutionalized civilian population residing throughout the whole of continental France was recruited from February 2006 to March 2007 for the French Nutrition and Health Survey. All individuals aged between 18 and 74 years who agreed to participate in the survey were included; thus there were 3115 participants, 2102 of whom were undergoing biochemical assessments. The prevalence of diagnosed diabetes was estimated using self-reported diabetes history and the prevalence of undiagnosed diabetes was estimated using fasting plasma glucose ≥ 7.0 mmol/l or HbA1c≥ 6.5% (≥ 48 mmol/mol).
Results The prevalence of diagnosed diabetes was 4.6%, 95% CI 3.6-5.7. The prevalence of undiagnosed diabetes according to standard fasting plasma glucose criteria was 1% (95% CI 0.6-1.7) and contributed to less than 20% of all cases of diabetes. This proportion decreased with age from 30% in 30- to 54-year-olds to 12% in 55- to 74-year-olds. Based on HbA1c criteria, the prevalence of undiagnosed diabetes was 0.8% (95% CI 0.4-1.6).
Conclusions The prevalence of diagnosed diabetes in adults in France is comparable with recent estimates from Northern Europe. The percentage of total diabetes that is undiagnosed is low in France, which may be explained by a widely practised strategy of opportunist screening. During the past years, improvements in diabetes care and increased awareness may have contributed towards decreasing the prevalence of undiagnosed diabetes more widely in Europe, and studies should further monitor such improvements.