OBJECTIVES: To compare health-related quality of life (HRQOL) using the Impact of Weight on Quality of Life-Lite (IWQOL-Lite) questionnaire in subjects with or without abdominal obesity (AO definition: waist circumference >102/88 cm for men/women, respectively). METHODS: Prospective Obesity Cohort of Economic Evaluation and Determinants (PROCEED) is an ongoing international, Internet-based, longitudinal, observational cohort of overweight/obese subjects [body mass index (BMI) > or = 25 kg/m2], aged 35-75, intending to lose weight. The IWQOL-Lite is a validated 31-item self-reported questionnaire, specifically designed for HRQOL assessment in obesity, and comprises 5 domains (Physical Function, Self-esteem, Sexual Life, Public Distress, Work) and a total score. Using two-sample t-tests, baseline IWQOL scores for USA subjects were compared between AO groups overall; between genders within the subgroup with AO; and between AO groups within overweight subgroup overall and within genders. RESULTS: Baseline analysis was conducted in overweight/obese subjects (BMI > or = 25 kg/m2) with AO (n=674, male 42%, female 58%, mean age 50, 91% Caucasian) and without AO (n=293, male 73%, female 27%, mean age 50, 88% Caucasian). Overall, subjects with AO reported a statistically significantly (p<0.05) lower total score and lower scores in all 5 domains compared with subjects without AO. In subjects with AO, women had statistically significant lower scores, for all domains and total score, compared with men (p<0.05). Overweight subjects (BMI 25-30 kg/m2) with AO (n=220) also reported a statistically significantly (p<0.05) lower total score compared with overweight subjects without AO (n=254), in the overall population, as well as in women. In men, the only difference observed was in the Physical Function score. CONCLUSION: AO was associated with impaired HRQOL (assessed using the IWQOL-Lite) for both men and women, with decreases for women being more marked. The data obtained in this Internet-based cohort are consistent with those from the literature.