Understanding the role of inequality of opportunity in body mass index and waist circumference among Mexican adults

Mexico faces one of the most acute obesity crises worldwide. While most of the literature has focused on studying the immediate causes of the phenomenon, very few have gone further to explore the structural causes of the public health problem, such as inequality of opportunity (IOp). The research agenda after the canonical work of John Roemer acknowledges that not all inequalities are equally illegitimate or unfair. The essence of the concept of inequality of opportunity relies on identifying the sources behind the variation of an outcome. Equality of opportunity is defined as a situation where individuals face equal circumstances (exogenous factors in which people do not have any control and therefore, cannot be held responsible for)for an outcome. This study aims to measure, identify and characterise the dynamics of the role of IOp in body mass index (BMI) and waist circumference (WC) for Mexican adults. Results show that inequalities in BMI and WC related to circumstances exist and vary between sex, geographical regions and percentiles of the distribution. Age and diabetes inherited from the parents are the main drivers of inequality. These findings highlight the need to design differentiated health policies that provide equality of opportunity; mitigate unequal circumstances of origin and compensate people for inherited unequal playing fields.