Mowafi et al. reported that no significant association was observed between socioeconomic status (SES) and overweight/obesity in Cairo, Egypt, using education, household expenditures, household assets, subjective wealth, and father’s education as indicators of SES [1]. Meanwhile, Ramsay et al. presented data indicating that socioeconomic position (SEP) was not significantly related to the prevalence of metabolic syndrome (MetS) when adjusted according to behavioral factors [2], although it was mentioned that behavioral factors such as physical activity, smoking, and alcohol consumption were responsible for the relationship between SEP and MetS.

Mowafi et al. mentioned that the selection of specific SES groups for obesity control intervention was difficult, and it is believed that the SES indicators should have been more widely selected in their study. This author has had the experience of performing a 3-year follow-up study to identify the effect of occupational position and shiftwork on the incidence of abdominal obesity after adjustments for lifestyle factors such as smoking, drinking, physical activity, and sleep. Occupational position, which is an SES indicator, did not contribute significantly to the incidence of abdominal obesity, although this finding should be validated in a longer follow-up study.

The relationship between SES and obesity seems to be complicated, and evaluations should also be adjusted according to ethnic and developmental factors. An exhaustive review on this topic has been updated by McLaren [3]. Obesity is a physical indicator, and various psycho-social factors influence obesity. For example, mental disorders are related to obesity [4,5], although a causal relationship cannot be clearly inferred. In author’s opinion, the observed relationship between SES and obesity may be confounded by unmeasured factors, such as personality and mental health states. These possible relationships should be explored by conducting careful surveys [6,7].