Abstract 57: Endocrine disruption in night shift workers

Background: The circadian timing system consists of a central brain clock in the hypothalamic suprachiasmatic nucleus and peripheral clocks in tissues, including the liver, muscle, adipose tissue and pancreas. Misalignment between different components of the circadian timing system, daily rhythms of sleep–wake behavior and food intake might contribute to the development of insulin resistance and altered hormonal regulation. There are limited number of studies in India on the hormonal and metabolic changes in Night shift workers and there are no studies particularly in the vulnerable night shift workers in software Multinational companies (MNC) in India. Objective: To Investigate the impact of Night shift work on Endocrine and metabolic Processes likeInsulin Resistance, Stress Response (Cortisol), Thyroid Axis and Gonadal Axis Material and Methods: This is a Cross sectional observational study done on total 90 subjects with 45 “Night Shiftworkers” with More than 3 months Night Shift work in MNC and 45 “Day shift workers”. Night shift work was defined as Work in Night of more than 6-8 hours crossing mid night and more than or equal to 5 days a week work. Data was collected using a pretested questionnaire meeting the objectives of the study. Detailed history, physical examination including anthropometry and necessary investigations have been done. Results and Discussion: Among Night shift workers statistically more number of subjects were having HOMA-IR > 2.5 (77.78% vs 62.23%) and more number of subjects qualified for subclinical hypothyroidism compared to day shift workers (22.22% vs 11.11%). The mean Triglycerides levels were elevated (212.42 md/dL vs 185.05 mg/dL) and HDL was low (35.4 mg/dL vs 39.8 mg/dL) among Night shift workers with significant P value. The mean 25 OH Vitamin D3 levels were low (9.95 ng/ml vs 15.09 ng/ml) among the night shift workers with significant P value. The Mean Serum 8 AM Cortisol in night shift workers are low (9.57 mcg/dL vs 11.11 mcg/dL) denoting reversal in cortisol rhythms compared to day shift workers. The Mean Estradiol levels in male night shift workers were higher (26.31 pg/ml vs 20.42 pg/ml) than the male day shift workers. Conclusion: The Night shift work is associated with increased risk of metabolic syndrome with Insulin resistance and dyslipidemia, Vitamin D deficiency, Subclinical Hypothyroidism, and reversal in Cortisol levels. There is need for further focused study to confirm these findings in a large prospective study.