# Comparison of young Japanese underweight women with eating disorder tendencies and constitutional thinness: A cross-sectional study

## TL;DR

This study compares underweight Japanese women with eating disorder tendencies and those with constitutional thinness to identify lifestyle and health factors that distinguish the two groups.

## Contribution

The study identifies anemia history and lifestyle habits as potential indicators for eating disorder tendencies in underweight women.

## Key findings

- Underweight women with eating disorder tendencies idealized thinner body shapes and reported greater dissatisfaction compared to those with constitutional thinness.
- A history of anemia was a significant predictor of eating disorder tendencies in underweight women.
- General health habits were similar between constitutional thinness and control groups but differed between eating disorder tendency and constitutional thinness groups.

## Abstract

To compare eating disorder tendencies and constitutional thinness in young underweight Japanese women and identify distinguishing factors.

In September 2024, 1000 young Japanese women were recruited and categorized into three groups based on body mass index (BMI) and responses to the Sick, Control, One Stone, Fat, and Food (SCOFF) questionnaire: eating disorder tendency (BMI <18.5 kg/m2 and SCOFF-positive, n = 93), constitutional thinness (BMI <18.5 kg/m2 and SCOFF-negative, n = 219), and control (BMI 18.5–25.0 kg/m2 and SCOFF-negative, n = 435).

The eating disorder tendency group idealized a thinner body shape than the constitutional thinness group and reported greater dissatisfaction with their body shape; however, body dissatisfaction was highest in the control group. General health habits were similar between the constitutional thinness and control groups. Among underweight women, significant predictors of eating disorder tendency included history of anemia (odds ratio [OR]: 4.27; 95 % confidence interval [CI]: 2.13–8.56), daily physical activity (OR: 3.46; 95 % CI: 1.78–6.74), and eating before bedtime (OR: 2.44; 95 % CI: 1.16–5.15).

General health habits differ between underweight women with and without eating disorder tendencies. A history of anemia may serve as a potential indicator for screening for eating disorders.

•Compared underweight women with/without eating disorder tendencies.•Underweight women with/without eating disorder tendencies differed in lifestyle.•Anemia history predicted eating disorder tendencies in underweight women.•Routine screening should assess eating disorder risk, including anemia history.

Compared underweight women with/without eating disorder tendencies.

Underweight women with/without eating disorder tendencies differed in lifestyle.

Anemia history predicted eating disorder tendencies in underweight women.

Routine screening should assess eating disorder risk, including anemia history.