Obesity as pleiotropic risk state for metabolic and mental health throughout life

Abstract

Obesity, a highly prevalent disorder and central diagnosis of the metabolic syndrome, is linked to mental health by clinical observations and biological pathways. Patients with a diagnosis of obesity may show long-lasting increases in risk for receiving psychiatric co-diagnoses. Austrian national registry data of inpatient services from 1997 to 2014 were analyzed to detect associations between a hospital diagnosis of obesity (ICD-10: E66) and disorders grouped by level-3 ICD-10 codes. Data were stratified by age decades and associations between each pair of diagnoses were computed with the Cochran-Mantel-Haenszel method, providing odds ratios (OR) and p values corrected for multiple testing. Further, directions of the associations were assessed by calculating time-order-ratios. Receiving a diagnosis of obesity significantly increased the odds for a large spectrum of psychiatric disorders across all age groups, including depression, psychosis-spectrum, anxiety, eating and personality disorders (all p_corr < 0.01, all OR > 1.5). For all co-diagnoses except for psychosis-spectrum, obesity was significantly more often the diagnosis received first. Further, significant sex differences were found for most disorders, with women showing increased risk for all disorders except schizophrenia and nicotine addiction. In addition to the well-recognized role in promoting disorders related to the metabolic syndrome and severe cardiometabolic sequalae, obesity commonly precedes severe mental health disorders. Risk is most pronounced in young age groups and particularly increased in female patients. Consequently, thorough screening for mental health problems in patients with obesity is urgently called for to allow prevention and facilitate adequate treatment.

Fig. 1. Time-ordering ratios for patients with a diagnosis of obesity and a respective psychiatric co-diagnosis grouped by two-digit ICD-10 F codes, stratified by sex.

Percentages of patients who receive both diagnosis at the same hospital stay, within a year, within 3 years and with a time gap of >3 years are presented for each sex. Lines in the upper half of the diagram indicate obesity to be the first diagnosis received while lines in the lower half indicate the respective psychiatric disorder to be the first diagnosis received. For example, when time between diagnoses exceeded three years a ratio of ~2 was observed for recurrent depressive disorder (F33), indicating that there were twice as many people diagnosed first with obesity than those diagnosed first with depression. Time-order-ratios tested for significance (*p < 0.05, **p < 0.01, ***p < 0.001).

Fig. 2. Percentages of patients with and without obesity with a diagnosed psychiatric disorder, grouped by two-digit ICD-10 F codes and by age decade.

p values are presented by levels of significance (*** p_corr < 0.001).

Fig. 3. Diagnosis rates for common psychiatric comorbidities stratified by presence and absence of a diagnosis of obesity (ICD-10: E66) and by sex.

Gender gaps towards male overrepresentation are seen in schizophrenia and nicotine use disorders, while all other comorbidities were showed increased risk in females. Gender gaps further widened in the presence of a diagnosis of obesity.

Fig. 4. Stratification by sex for patients with a diagnosis of obesity and a respective psychiatric co-diagnosis grouped by two-digit ICD-10 F codes.

Odds ratios (OR) with confidence intervals are presenting the risk of being female or male when a respective psychiatric co-diagnosis is received for each age group. Corrected p values are presented by levels of significance (*p < 0.05, **p < 0.01, ***p < 0.001).