Shift work aggravates metabolic syndrome developmentamong early-middle-aged males with elevated ALT

Abstract

AIM:To examine whether shift work accelerates metabolic syndrome (MetS) development among early middle-aged males with elevated alanine aminotransferase (e-ALT). METHODS:A retrospective, observational followup study on MetS development at a 5-year interval was conducted using health examination data. Nine hundred and ninety six male employees not fulfilling MetS criteria at screening were enrolled. Age, MetScomponents, liver enzymes, serological markers for viral hepatitis, abdominal ultrasound, insulin resistance status, lifestyles, and workplace factors were analyzed. RESULTS:The prevalence of elevated serum ALT (> 40 U/L, e-ALT) at baseline was 19.1%. There were 381 (38.3%) workers with long-term exposures to daynight rotating shift work (RSW). 14.2% of subjects developed MetS during follow-up. After 5 years, the workers with e-ALT had significantly unfavorable changes in MetS-components, and higher rates of MetS development, vs subjects with normal baseline ALT levels. Workers with both baseline e-ALT and 5-year persistent RSW (pRSW) exposure had the highest rate of MetS development. Also, e-ALT-plus-pRSW workers had a significant increase in MetS-components at follow-up, compared with the other subgroups. After controlling for potential confounders, e-ALT-plus-pRSW workers posed a significant risk for MetS development (odds ratio, 2.7; 95% confidence interval, 1.4-5.3, vs workers without baseline e-ALT nor pRSW). CONCLUSION:We suggest that all early middleaged male employees with e-ALT should be evaluated and managed for MetS. Particularly in terms of job arrangements, impacts of long-term RSW on MetS development should be assessed for all male employees having baseline e-ALT.

Elevated alanine aminotransferase activity is not associated with dyslipidemias, but related to insulin resistance and higher disease grades in non-diabetic non-alcoholic fatty liver disease

“…To our knowledge, the present study is the first that shows non diabetic NAFLD patients representing a higher serum ALT level are significantly more likely to have higher NAFLD grades. It has been previously shown that serum ALT is associated with insulin resistance in NAFLD patients [30] , but our finding is in a population after exclusion of diabetic patients. Another interesting finding of the current study is that abnormal ALT levels, independent to NAFLD severity grade, is significantly associated with insulin resistance.…”

“…This makes our study unique. Some previous studies have suggested that elevated ALT levels and fatty livers were independently associated with increased risk of metabolic syndromes [29,30] . On the other hand, consistent to our results, a community-based study in Taiwan, a country with a relatively low prevalence of diabetes mellitus [31] showed no increased prevalence of metabolic syndrome for NAFLD patients with elevated ALT levels.…”

“…ALT levels were considered pathologically high when it was over 30 IU/L for men and over 19 IU/L for women.…”

“…Thereby, at the first step, we need to know hypothesis on the pathogenesis of NAFLD and factors playing major roles in this process, to be able to adjust these factors in a way Alanine 30 IU/L for men and over 19 IU/L for women. Results: Bivariate analyses using t test and chisquare test showed that patients with pathologically augmented ALT levels had significantly higher NAFLD grades in their ultrasonographic evaluations (P=0.003).…”

Excessive 5-year weight gain predicts metabolic syndrome development in healthy middle-aged adults

“…Nevertheless, we treated waist circumference as a confounder in the multivariate analysis (Table 5) because it has a decisive influence on the development of metabolic syndrome. On the other hand, occupational and lifestyle factors naturally affect dietary behaviors and thus affect body weight changes [19] and other factors of atherosclerosis which are important in MetS development, including total cholesterol, low density lipoprotein cholesterol, uric acid and insulin. Our present study focused on body weight changes, and although we controlled some occupational, lifestyle and baseline metabolic factors (not shown in tables), the detailed impact of these factors needs to be clarified by other investigations.…”