Is low Weight Disorder (Anorexia Nervosa) Correlated with Gender, Socio Demographic and Psychological Features?

Abstract

The objective of the current study is to examine the economics, socio-demographic and psychological determinants of the probability to suffer from low-weight disorder or anorexia nervosa. Unlike the vast literature on obesity, fewer studies have investigated the opposite phenomena, namely, low-weight disorder or anorexia. Given the extra difficulty to diagnose anorexia via Diagnostic and Statistical Manual of Mental Disorders (DSM) validated questionnaires, the advantage of our study lies in the simple quantitative measure we use of BMI≤18. This criterion might be a suitable measure to a western developed country like Israel, in which the probability that BMI<=18 reflects chronic energy deficiency due to circumstances of poverty and/or lack of access to food is small. We make use of an extensive set of questions concerning the economic and socio-demographic features, health and housing conditions of each respondent asked within the framework of the 2015-2016 longitudinal survey conducted by the Israeli Central Bureau of Statistics (CBS). The survey also includes information regarding the weight, height, gender and age of each household member. Results indicate a significant decrease in the projected probability of having BMI≤18 with age. Compared with the 21-67 year old cohorts, the relative frequency of BMI≤18 rises to 10.68%-16.83% for the 10-20 year-old cohorts. For the female (male) respondents, projected probability drops consistently from 50% (75%) at the 10-year-old cohort to about 0% at the 62- (67-) year-old cohort. These figures imply that low-weight disorder or anorexia is a typical around the projected probability of having BMI≤18. While this spread ranges between 30.67% and 68.64% for 10-year-old females (a range of 37.97%), the same spread ranges between 67.10% and 82.79% for 10-year-old males (a range of only 15.69%). For both gender, this spread around the projected probability drops with the age variable. For female respondents, projected probability of having BMI≤18 significantly drops with age, homeownership and European-American immigration status, and significantly rises with residence in a standard apartment in multi-story structure. For male respondents, projected probability of BMI≤18 drops significantly with age and with having a home library that includes at least one book, and rises significantly with the household size, and European-American immigration status. Interestingly, for female cohorts of 10-20 years, projected probability of BMI≤18 rises significantly from 4.4157% to 16.6627% with reported good health conditions. This outcome may be interpreted as self-denial of young female respondents regarding their realistic health conditions, and might support the definition of BMI≤18 as anorexia nervosa.