Nagaya Teruo, Yoshida Hideyo, Takahashi Hidekatsu, Kawai Makoto
Department of Public Health, Nagoya City University Medical School, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
Int Arch Occup Environ Health. 2002 Oct;75(8):562-8. doi: 10.1007/s00420-002-0370-0. Epub 2002 Aug 14.
To examine relationships between shift work and markers (metabolic abnormalities) of insulin resistance (IR).
A cross-sectional study of 2,824 day and 826 shift workers. All the subjects were male blue-collar workers aged 30-59 years. Four IR markers [(1) hypertension (systolic blood pressure >or=140 mmHg or diastolic blood pressure >or=90 mmHg or under treatment for hypertension); (2) hyperglycemia (fasting serum glucose >or=7.00 mmol/l or under treatment for diabetes); (3) hypertriglyceridemia (fasting serum triglyceride >or=1.70 mmol/l or under treatment for hyperlipidemia); (4) hypo-HDL-cholesterolemia (fasting serum HDL-cholesterol <1.04 mmol/l)] were checked. Subsequently, IR syndrome, a cluster of IR markers, was expediently diagnosed by the number (N) of IR markers found in each worker. N>or=1, N>or=2 or N>or=3 was used as a cutpoint for the diagnosis. The prevalence of each IR marker and IR syndrome was compared between the two worker groups. Age, body mass index (kg/m(2)), job, drinking, smoking, and exercise were used as confounding factors. Job, work schedule and lifestyles were based on self-administered questionnaires.
Hypertriglyceridemia (28.7% in day workers, 31.2% in shift workers) was most prevalent (4.6%), and hyperglycemia (5.4%) was least, in the four IR markers in both worker groups. Approximately half of the subjects had at least one IR marker in both groups (N>or=1; 46.0% and 46.6%, respectively). However, a full cluster of IR markers was rare in both groups (N=4; 0.2% and 0.1%, respectively). Prevalence of IR syndrome by any cutpoints increased with age in day workers, but shift workers aged 50 years or older had lower prevalence than shift workers younger than 50 years. In subjects younger than 50 years, all IR markers (except for hypo-HDL-cholesterolemia) and IR syndrome by any cutpoints were more prevalent in shift workers than in day workers. Contrariwise, in subjects aged 50 years or older, lower prevalence of all IR markers and IR syndrome in shift workers than in day workers was found. These results were not influenced by statistical adjustments for the confounding factors by multiple logistic regression analysis.
Shift work may be associated with IR syndrome in workers younger than 50 years. These relations may be underestimated mainly by broad definition of shift work and healthy-worker effects.
研究轮班工作与胰岛素抵抗（IR）标志物（代谢异常）之间的关系。
对2824名日班工人和826名轮班工人进行横断面研究。所有受试者均为30至59岁的男性蓝领工人。检查了四个IR标志物：（1）高血压（收缩压≥140 mmHg或舒张压≥90 mmHg或正在接受高血压治疗）；（2）高血糖（空腹血清葡萄糖≥7.00 mmol/l或正在接受糖尿病治疗）；（3）高甘油三酯血症（空腹血清甘油三酯≥1.70 mmol/l或正在接受高脂血症治疗）；（4）低高密度脂蛋白胆固醇血症（空腹血清高密度脂蛋白胆固醇<1.04 mmol/l）。随后，根据每个工人发现的IR标志物数量（N），便捷地诊断出IR综合征，这是一组IR标志物。N≥1、N≥2或N≥3被用作诊断的切点。比较两组工人中每个IR标志物和IR综合征的患病率。年龄、体重指数（kg/m²）、工作、饮酒、吸烟和运动被用作混杂因素。工作、工作时间表和生活方式基于自我填写的问卷。
在两组工人的四个IR标志物中，高甘油三酯血症最为普遍（日班工人中为28.7%，轮班工人中为31.2%），高血糖最少（5.4%）。两组中约一半的受试者至少有一个IR标志物（N≥1；分别为46.0%和46.6%）。然而，两组中IR标志物的完整组合都很少见（N = 4；分别为0.2%和0.1%）。日班工人中，任何切点的IR综合征患病率随年龄增加而升高，但50岁及以上的轮班工人患病率低于50岁以下的轮班工人。在50岁以下的受试者中，所有IR标志物（除低高密度脂蛋白胆固醇血症外）和任何切点的IR综合征在轮班工人中比在日班工人中更普遍。相反，在50岁及以上的受试者中，发现轮班工人中所有IR标志物和IR综合征的患病率低于日班工人。这些结果不受多因素logistic回归分析对混杂因素进行统计调整的影响。
轮班工作可能与50岁以下工人的IR综合征有关。这些关系可能主要因轮班工作的宽泛定义和健康工人效应而被低估。
