The risk of cardiovascular disease (CVD) and type 2 diabetes mellitus (DM) associated with obesity appears to be influenced by the coexistence of other metabolic abnormalities.

We examined the risk of developing CVD and DM in metabolically healthy obese (MHO) and metabolically unhealthy normal weight (MUH-NW) individuals.

We analyzed prospective data of the San Antonio Heart Study, a population-based study among Mexican Americans and non-Hispanic whites (median follow-up, 7.4 y).

Incident DM and CVD were assessed in 2814 and 3700 participants aged 25 to 64 years, respectively.

MHO was defined as obesity (body mass index ≥ 30 kg/m²) with no more than one metabolic abnormality, and MUH-NW was defined as body mass index <25 kg/m² with two or more abnormalities.

In logistic regression models, BMI was associated with incident DM after controlling for demographics, family history of DM, and fasting glucose (odds ratio × 1 SD, 1.7 [95% CI, 1.5–2.0]). Both MUH-NW and MHO individuals had an increased DM risk (2.5 [1.1–5.6] and 3.9 [2.0–7.4], respectively). Similarly, BMI was related to incident CVD after adjusting for demographics and Framingham risk score (1.3 [1.1–1.6]). Incident CVD was also increased in MUH-NW and MHO individuals (2.9 [1.3–6.4] and 3.9 [1.9–7.8], respectively). Results were consistent across gender and ethnic categories.

The risk of developing DM and CVD is increased in MUH-NW and MHO individuals. Screening for obesity and other metabolic abnormalities should be routinely performed in clinical practice to institute appropriate preventive measures.