Relation between sleeping time and obesity along the shift work of adult workers

Abstract

While workers in various social areas are doing shift works, workers who don’t adjust to them are suffering from destruction of body and life rhythms and having safety accidents and health problems arisen from physical and mental difficulties. Studies on wrong eating habits and sleep disorders handled various job shift and heath problems focusing on sleeping problems related with stress, quality of life and disease and there are several studies on correlations with obesity increase. So, this study intended to find several factors affecting obesity for adult workers and if there is any correlation between sleeping time and obesity. This study took 2,088 objects with regular jobs (656 persons with shift works and 1,432 persons with normal works) in the order of sleeping time, height, and weight excluding 31 persons’ result measured values for 2,119 regular workers out of more than 19 year old 25,122 persons from 22,809 persons of total study objects at the first year (2010) health investigation of 4th and 5th National Health/Nutrition Survey. In order to classify the work pattern into the shift work and normal work and find out the relation between obesity and demographic factor (gender, age and marriage) that is the confounding factor, social & economical factor (income level & educational level) and health pattern factor (smoking, drinking, sleeping time, walking practice, stress, frequency of eat out & amount of energy intake), the factors that influences on the relation between sleeping time and obesity along the shift work were investigated by performing logistic regression analysis and analyzing odds ration after classifying them into model #1 which corrects gender, sleeping time and work pattern only, model #2 which corrects the interaction between sleeping time and work pattern only to model #1 and model #3 which corrects all factors. It showed the significant difference statistically in gender & sleeping time in case of model #1 which corrects gender, sleeping time and work pattern only and the probability of male of having obesity was higher than female by 2.5 times(95% CI 2.08-3.14) and sleeping time was higher by 1.4 times(95% CI 0.88-1.49) in case of less than 6 hours based on above 8 hours. It showed the significant difference statistically in gender & sleeping time in case of model #2 which corrects the interaction of work pattern only from model #1 and the probability of male of having obesity was higher than female by 2.5 times(95% CI 2.07-3.14) and sleeping time was higher by 1.2 times(95% CI 0.96-1.74) in case of less than 6 hours based on above 8 hours. It showed the significant difference statistically in gender, educational level & sleeping time in case of model #3 which corrects all factors and the probability of male of having obesity was higher than female by 2.3 times(95% CI 0.45-0.94) and the difference of educational level was significant as it showed 0.65 times(95% CI 0.45-0.94) and 0.66 times(95% CI 0.45-0.98) each in cases of above high school graduates and university graduates based on below middle school graduates. Regarding sleeping time, the probability of having obesity was higher by 1.5 times(95% CI 1.11-2.03) in case of less than 6 hours based on above 8 hours of sleeping time. As the result of interacting between work pattern and sleeping time, the result of comparing sleeping time and obesity along shift work and normal work between model #2 and #3 did not show the significant difference statistically.

본 연구는 교대근무에 따른 수면시간과 비만의 관련 요인 분석을 위하여 국민건강·영양조사 제4기, 제5기 1차년도(2010)조사 건강조사 중 총 연구 대상자 33,809명에서 만19세 이상 성인인 25,122명중 취업자중 상용직인 2,119명을 수면시간, 신장, 체중의 순서로 31명의 결측치를 제외한 2,088명(교대근무 656명, 정상근무 1,432명)을 대상으로 하였다. 비만에 영향을 미치는 영향을 알아보기 위해 근무형태를 교대근무와 정상근무로 분류하고, 혼란변수인 인구학적 요인(연령, 성별, 결혼유무), 사회·경제학적 요인(소득수준, 교육수준), 건강 행태 요인(흡연여부, 음주유무, 수면시간, 걷기운동, 스트레스, 외식 빈도, 에너지 섭취량)과 비만과의 관계를 알아보기 위해 성별, 수면시간, 근무형태를 보정한 Model 1, Model 1에 수면시간과 근무형태의 상호작용만 보정한 Model 2, 모든 변수를 보정한 Model 3으로 분류하여 로지스틱 회귀분석(logistic regression analysis)을 시행하고, 교차비(odds ratio)를 분석하여 교대근무에 따른 수면시간과 비만의 관련에 영향을 미치는 요인을 알아보았다. 성별, 수면시간, 근무형태만 보정한 Model 1에서는 성별, 수면시간에서 통계적으로 유의한 차이를 보였으며 남자가 여자보다 비만할 확률이 2.5배(95% CI 2.08-3.14)높았고, 수면시간은 8시간 이상을 기준으로 6시간 미만 1.4배(95% CI 0.88-1.49)높았다. Model 1과 근무형태의 상호작용만 보정한 Model 2에서는 성별, 수면시간에서 통계적으로 유의한 차이를 보였으며 남자가 비만할 확률이 2.5배(95% CI 2.07-3.14)높았고, 수면시간 8시간 이상을 기준으로 6시간 미만 1.2배(95% CI 0.96-1.74)높았다. 모든 변수를 보정한 Model 3에서는 성별, 교육수준, 수면시간에서 통계적으로 유의한 차이를 보였으며 성별은 남자가 여자보다 비만이 발생할 확률이 2.3배(95% CI 0.45-0.94)높았다. 교육수준은 중학교 졸업 이하를 기준으로 고등학교 졸업, 대학교 졸업 이상에서 각각 0.65배(95% CI 0.45-0.94), 0.66배(95% CI 0.45-0.98)높았으며, 이는 통계학적으로 유의하였다. 수면시간은 8시간 이상의 수면시간을 기준으로 6시간 미만에서 비만이 발생할 확률은 1.5배(95% CI 1.11-2.03)이었고, 이는 통계학적으로 유의한 차이를 보였다. 근무형태와 수면시간의 상호작용(interaction) 결과는 Model 2, Model 3의 교대근무와 정상근무에 따른 수면시간과 비만은 통계학적으로 유의한 차이가 없었다.