Night-shift work, sleep disturbance, and obesity risk: A review of epidemiological evidence and biological mechanisms in Thailand

Abstract

Obesity is a major global public health challenge and an important risk factor for non-communicable diseases (NCDs), including cardiovascular disease, type 2 diabetes mellitus, and metabolic syndrome. Increasing evidence suggests that night-shift work and sleep disturbance may contribute to obesity through circadian disruption, hormonal dysregulation, metabolic impairment, and behavioral changes. These issues are becoming increasingly relevant in Thailand due to rapid urbanization and expansion of shift-based labor systems. This narrative review aimed to synthesize current epidemiological evidence and biological mechanisms linking night-shift work, sleep disturbance, and obesity risk, with particular emphasis on the Thai context. A structured narrative review was conducted using PubMed, Scopus, Google Scholar, and Thai Journals Online (ThaiJO). The literature search was performed between August and October 2025 and included studies published between January 2000 and October 2025. Search terms related to night-shift work, sleep disturbance, circadian disruption, obesity, metabolic syndrome, and Thailand were applied. Of approximately 120 initially identified articles, 24 studies met the predefined inclusion criteria and were included in the final review. Evidence was synthesized narratively due to heterogeneity in study designs and outcome measures. Current evidence consistently indicates that night-shift workers are at increased risk of overweight, abdominal obesity, metabolic syndrome, and impaired glucose metabolism compared with day workers. Meta-analyses report that night-shift workers have approximately a 23% higher risk of overweight or obesity and a 35% greater likelihood of abdominal obesity. Biological evidence suggests that sleep deprivation and circadian misalignment alter appetite-regulating hormones, impair insulin sensitivity, and disrupt energy metabolism. Thai studies, although limited, demonstrate similar patterns, particularly among healthcare workers and individuals with metabolic disease exposed to irregular work schedules. Night-shift work and sleep disturbance appear to be important occupational determinants of obesity and metabolic dysfunction. Circadian disruption, hormonal alterations, and behavioral adaptations may collectively contribute to increased obesity risk among shift-working populations. Integrating sleep health and occupational considerations into obesity prevention and public health strategies may help reduce the growing burden of obesity and related NCDs, particularly in rapidly developing countries such as Thailand.