Association between underweight and low lymphocyte count as an indicator of malnutrition in Japanese women

The number of young women who are underweight has recently increased in Japan. The aim of the present study was to investigate the nutritional problems of young Japanese women by measuring serum albumin, prealbumin, and lymphocyte count as indicators of nutritional status.The subjects were 912 women aged 19-39 years who participated in an annual health checkup for residents in a city of Aichi prefecture, Japan. Questionnaire data, physical measurements, and blood tests were analyzed in relation to weight categories of underweight (body mass index [BMI]18.5 kg/m(2)), normal (BMIor =18.5-25 kg/m(2)), and obese (BMIor =25 kg/m(2)).Lymphocyte counts were significantly lower in the underweight group. A multivariate logistic regression analysis showed an association of low lymphocyte count (1500/microL) with underweight (odds ratio [OR] 1.96, 95% confidence interval [CI] 1.35-2.83). Low prealbumin (20 mg/dL) was associated with weight loss (OR 1.42, 95% CI 1.00-2.02) but not with underweight. Albumin was not lower in the underweight group. The prevalence of low lymphocyte count was higher by 35% among underweight women who lost weight ofor =1 kg in the past 3 months and higher by 50% among those who lost weight ofor = 2 kg.The present study suggests that underweight women in their 20s and 30s can be at risk for low lymphocyte count or potential malnutrition. The risk is particularly high in underweight women who have lost weight in recent months.