Older adult women with chronic anorexia nervosa: heterogeneous adaptation to undernutrition over time

Anorexia nervosa (AN) in older adult women is primarily described through reviews or case reports focusing on psychiatric traits, with no comprehensive studies evaluating their complete nutritional and hormonal profiles. This study aimed to describe a group of women with anorexia nervosa aged above 35 years old (AN35), and compare them with young women with anorexia nervosa (ANY) and normal-weight control participants. Anthropometric, metabolic, nutritional, and psychiatric parameters were collected and compared among three groups of women: 50 AN35, 37 ANY, and 38 controls. AN35 exhibited a mean disease duration of 271 ± 19 months, with 94% chronic forms and 58% restrictive types. Despite having similar BMI as ANY, AN35 displayed more altered parameters, including higher liver enzymes (p = 0.007), free T3 (p = 0.0046) and leptin (p < 0.0001); and lower albumin (p = 0.0029), and white cells (p < 0.0001). AN35 showed significant heterogeneity in hormonal adaptation, such as free T3. Half of the patients aged above 51 years revealed high gonadotropin levels despite being undernourished. Additionally, AN35 groups presented with 50% of bones fractures, decreased T-scores under -2.5 (p < 0.0001 for femoral), and altered micro architectural HRPQT parameters compared to ANY. Anorexia nervosa in older adult women is predominantly chronic. Nutritional parameters changes with age suggests a significant heterogeneity and possible adaptation of energy balance and bodyweight set point for others. Complications may be severe, altering the quality of life, and sometimes potentially lethal. These findings highlight the potential adaptation of energy balance with age, and should assist clinicians in clinical practice.