Conclusion: Occupation transition from employed to unemployed status was found to increase risk of ... important role in risk of cardiovascular disease (CVD),.
METABOLIC SYNDROME AND RELATED DISORDERS Volume 14, Number 5, 2016 Mary Ann Liebert, Inc. Pp. 265–271 DOI: 10.1089/met.2015.0125
The Relationship Between Occupation Transition Status and Metabolic Syndrome in Adult Women: Tehran Lipid and Glucose Study Parvin Mirmiran, PhD,1 Golaleh Asghari, PhD,1 Hossein Farhadnejad, MSc,1 Shahram Alamdari, MD,2 Alireza Dizavi, MSc,1 and Fereidoun Azizi, MD3
Abstract
Purpose: Although occupation status may play a role in the risk of metabolic syndrome (MetS), data on this topic are limited. The aim was to examine the association between occupation transition status and the 12-year incidence of MetS in adult women of a population-based cohort study. Methods: A total of 2406 women, aged ‡20 years, were selected from the Tehran Lipid and Glucose Study. Subjects were free of MetS at baseline and followed for a mean of 12 years. Based on occupation transition from baseline to the end of follow-up, women were classified into four groups: employed–employed (group I), employed–unemployed (group II), unemployed–employed (group III), and unemployed–unemployed (group IV). The odds ratio (OR) for the occurrence of MetS and its components according to occupation transition status was assessed by multivariate logistic regression. Results: The incidence of MetS in group I and group IV was 15.6% and 29.3%, respectively. In comparison with women in group I, those in group IV had higher risk of MetS (OR = 2.45, 95% CI, 1.6–3.8); however, after adjustment for age, education level, marital status, smoking, and body mass index, the association between occupation status and MetS was not significant (OR = 1.38, 95% CI, 0.83–2.27). In the fully adjusted model, women who were employed at baseline and unemployed at the end of follow-up had greater risk of incident MetS (OR = 2.26, 95% CI, 1.26–4.06) and low high-density lipoprotein cholesterol (OR = 2.34, 95% CI, 1.40– 3.85) compared with those who were constantly employed. Conclusion: Occupation transition from employed to unemployed status was found to increase risk of incident MetS.
Introduction
M
etabolic syndrome (MetS), an abnormal complex disorder characterized by abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), hypertension, and hyperglycemia, can play an important role in risk of cardiovascular disease (CVD), coronary heart disease, or type 2 diabetes.1,2 This abnormality is prevalent and affects 20%–25% of adults worldwide,3 25% in the United States,4 and 30% in Iran.5 Etiology of MetS has not been clearly elucidated; however, the interaction of genetic, metabolic, and environmental factors, such as smoking, alcohol consumption, diet, chronic stress, physical inactivity, education level, income, and occupation, is believed to increase the risk of MetS.6–10
The impact of occupation transition status on health has been investigated in some studies.11–13 Gebel and Vossemer indicated that people who lose their job had worse psychological and physical health in comparison with those who are continuously employed.11 In addition, mental health improvement has been seen in occupation transition to employed status,12 whereas in one study, retirement, a major life transition, was related to decreasing both mental and physical fatigue.13 Therefore, the role of occupation as a socioeconomic factor on the risk of MetS has been investigated.14–18 Some studies have indicated that occupation through physical activity level and income have association with risk of MetS18,19; the effect of job strain has been investigated in relation to the risk of MetS.17 However, studies in women are limited to two cross-sectional investigations,14,15
1 Nutrition and Endocrine Research Center, 2Obesity Research Center, and 3Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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indicating a lower prevalence of MetS in employed women compared with housewives14 and a decreased risk of MetS in postmenopausal women, but not in premenopausal ones.15 To the best of our knowledge, the relationship of occupation transition with the incidence of MetS in healthy women has not been evaluated. Hence, this study was designed to evaluate the association between occupation transition during a 12-year follow-up and incidence of MetS in a large population-based cohort of Tehranian women aged over 20 years.
Materials and Methods Subjects The Tehran Lipid and Glucose Study (TLGS) is a population-based cohort study designed to determine the risk factors of noncommunicable diseases among a representative urban population of Tehran.20,21 At baseline, 4751 families, including over 15,000 residents aged 3 years or older, were recruited by multistage cluster random sampling method from district 13 of Tehran, the capital of Iran; this district is located in the center of Tehran. The age distribution of the TLGS is representative of the overall population of Tehran. The participants were followed up every 3 years; the baseline survey was cross-sectional (1999–2001), and surveys 2 (2002–2005), 3 (2006–2008), 4 (2009–2011), and 5 (2012–2014) were prospective followup surveys. For the current study, women aged ‡20 years at baseline were selected (n = 7196). After excluding those with missing occupation, anthropometric, and biochemical data (n = 1345), those with history of CVD (n = 141) and those with MetS (n = 2044) at baseline, 3666 women, remained. Some individuals fell into more than one exclusion category. Of 3666 participants, 2406 were followed to survey 5 (2012–2014) for a median of 12 years (follow-up rate: 66%). The ethics committee of the Research Institute for Endocrine Sciences approved this study. All subjects gave written informed consent for participating in this study.
Measurements Pretested questionnaires were used to collect information on sociodemographics, anthropometrics, medical history of CVD, medication use, and smoking habits. Height, weight, waist circumference (WC), blood pressure, and biochemical markers were measured, and body mass index (BMI) was calculated. To assess the socioeconomic status, information on women’s marital status and level of education was obtained. Weight was recorded while the subjects were minimally clothed using digital scales and recorded to the nearest 100 grams. Shoes and socks were removed before measurements were performed. Height was measured in a standing position, without shoes, using a stadiometer while the shoulders were in a normal position. BMI was computed as weight in kilograms divided by height in meters squared. WC was measured at the abdominal level, at the umbilical level, over light clothing, using an unstretched shape tape meter, and without any pressure to body surface, and measurements were recorded to the nearest 0.1 cm. Using a standard mercury sphygmomanometer, systolic and diastolic blood pressures were measured twice in a sitting position after a resting period of 15 min. Biochemical tests included serum total cholesterol (TC), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-
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C), HDL-C, and fasting plasma glucose (FPG). A blood sample was taken after a 12- to 14-hour overnight fast in a sitting position according to the standard protocol and centrifuged within 30–45 min of collection. All blood analyses were done at the TLGS research laboratory on the day of blood collection. The analysis of samples was performed using Selectra 2 autoanalyzer (Vital Scientific, Spankeren, The Netherlands). FPG was measured using an enzymatic colorimetric method with glucose oxidase. Inter- and intraassay coefficients of variation (CVs) were both 2.2% for FPG. For measurement of TGs, we used an enzymatic calorimetric method with glycerol phosphate oxidase. Interand intra-assay CVs for TGs were 0.6% and 1.6%, respectively. TC was assessed with cholesterol esterase and cholesterol oxidase using the enzymatic colorimetric method. After precipitation of apolipoprotein b with phosphotungstic acid, HDL-C was measured. Inter- and intra-assay CVs for both TC and HDL-C were 0.5% and 2%, respectively. LDL-C was calculated from the serum TC, TG, and HDL-C concentrations expressed in mg/dL using the Friedewald formula.22 These analyses were performed using commercial kits (Pars Azmoon, Inc., Tehran, Iran).
Definition of outcome MetS was determined as the presence of three or more of five following components as recommended by the joint interim statement23 and new cutoff points of WC for Iranian adults24: hyperglycemia: FPG ‡100 mg/dL or drug treatment of impaired fasting glucose; hypertriglyceridemia: TGs ‡150 mg/dL or drug treatment; low HDL-C: serum HDL-C
