محسن روضاتی

Metabolic syndromes have been identified as a major risk factor for people with cardiovascular disease. Metabolic syndromes are defined as a range of conditions including waist-fat, abdominal obesity, high blood pressure, diabetes, high triglycerides, and HDL. Considering the importance of controlling metabolic syndrome, the research study subject with the mentioned aim is so important in the world and Iran. One of the affecting factors that have reported contradictory results in the previous study are shift work. Therefore, this prospective cohort study was conducted to investigate the relationship between metabolic shift syndromes on labor men.

This five-year prospective cohort study has been conducted in randomly selected workers (using random cluster sampling) who work in Esfahan’s Mobarakeh Steel Company (the largest steel company in Iran country that located in Mobarkeh city in Isfahan province, Iran) from April 2011 March 2015. In this study shiftwork and metabolic syndromes considered as an independent and dependent variable respectively. In addition, age, education and work experience considered as a controlling variable. In this study, routinely rotating (ROR) and weekly rotating (WRO) shifts were scheduled with a clockwise rotation plan (two mornings, two evenings, two night and two days off for ROR and three morning shifts, three evening shifts, and one day off every two weeks, Fridays always off for WRO shifts). The morning, evening, and night shifts began at 7 AM, 3 PM, and 11 PM, respectively. Day workers (DW) worked from 7 AM to 3 PM on weekdays and had Thursdays and Fridays off.

The study sample included 1321 male workers (mean age=43). Among these subjects, 528 (40%), 155 (12%) and 638 (48%) were day workers, WRO shift workers, and ROR. The 5-year odds ratio (OR) of metabolic syndrome in the ROR shift worker compared to the DW was OR=1.93, P-value=0.044 and for a WRO shift with OR=1.26, P=0.64.

Considering the result of this study increased risk of metabolic syndrome in ROR shift worker rather than DW has been approved but such increase in WRO shift rather day worker had not to be approved.

In today's competitive environment, organizations focus on issues that affect cost and productivity, such as absenteeism due to illness (sick leave). According to the importance of this subject, this study done with the aim of study of effective factors on the number of sick leave days. This longitudinal study was conducted on workers of Esfahan’s Mobarakeh Steel Company during 2011- 2015. In this study, was used model multilevel path analysis with Poisson's response and MPLUS software was used to analyze such data. Findings: This study includes 7020 participants with the average age of 38.89 years. The results of the study showed that in within-group level variables of age, education and disease (cardiovascular disease, arthritis and osteopathy disease, indigestion, endocrine and cancer) have direct effect and variables of work experience and Framingham score have indirect effect on the number of sick leave days. In addition in between-group level the possibility of shift work and being a smoker has a direct effect on the number of the sick leave days. The results from the study shows that shift work workers are more exposed to disease that eventually results in an increase in the number of their sick leave days than day workers

  The Cox model is one of the methods used in survival data; however, the use of hierarchical data, such as the data of this study, violates the assumption of independence, the the Cox model cannot be used assuming independence of observations. One of the important methods for analyzing survival hierarchy data is the use of the multilevel Cox model. In this method, in addition to modeling the response variable, regression coefficients are also modeled and the measurement error resulting from the lack of data independence is reduced. The present study used a multilevel Cox model to investigate the effect of the retention of antihypertensive drugs in people with hypertension.

This longitudinal survival study was conducted in 346 workers with hypertension in Mobarakeh Steel Company in Isfahan. During the years 1390-1394, when the staff attended the health center in the factory, they were treated with six drugs, including captopril, losartan, atenolol, propranolol, amlodipine, and hydrochlorothiazide. In order to examine the relationship of the retention of drugs with job experience, body mass index, and drug history, a two-level Cox model was used as h_ij (t)=h_0 (t)exp⁡(α_g+x_ij β_j), where i and j is the first and second level units, respectively.

During five years, the findings of model fitting showed the effect of body mass index (P = 0.019), atenolol (P=0.046), and amlodipine (P=0.021) in a single form, and the effect of losartan-amlodipine (P=0.042) and atenolol-hydrochlorothiazide (P = 0.003) in a combination form were significant.

Based on the study results, the most effective drugs for hypertension control are amlodipine monotherapy, amlodipine-losartan combination therapy, and atenolol monotherapy, respectively.

Detection of appropriate models for the distribution of property population is very important. In the present study, the combined mixture distributions and multi-level analysis with Bayesian approach were used to determine the relationship between shift work and Framingham Risk Score (FRS).
The model designed to evaluate the relationship between shift work and the Framingham score was utilized on the data obtained in a cross-sectional study on 3243 workers of Mobarakeh Steel Company, Iran, in the first 6 months of 2015.
Findings: The workers consisted of 1690 day workers with a mean age of 42.13 ± 6.13, 1356 routine rotating shift workers with mean age of 40.75 ± 6.09, and 197 weekly rotating shift workers with mean age of 41.60 ± 6.10. In this study, by controlling the confounding factors, shift work showed a statistical relationship with FRS.
According to the results of this study, the FRS was higher among shift workers than day workers. This result has been supported by previous studies.

Previous studies have reported contradictory results regarding the association of Shift Work (SW) and Blood Cholesterol (BC). In this paper, we studied the relationship between SW and BC. The data of this historical cohort study was extracted from annual observations of the workers of Esfahan’s Mobarakeh Steel Company selected through cluster random sampling between 1996 and 2011. In this research, we assessed the effect of SW on BC with controlling BMI, age, work experience, marital status, smoking, and educational status. Five hundered and seventy four male workers participated in this study with a mean (SD) age of 41.89 (7.51) and mean (SD) work experience of 16.75 (7.16) years. In this study, after controlling confounding factors, we found no significant relationship between SW and BC. Because our study showed no relationship between SW and BC, we can state that this relationship does not exist with more certainty.

Nowadays there has been an increasing interest in more flexible distributions like skew distributions that can represent observed behavior more closely. These distributions are often used in the medical and behavioral sciences for real-valued random variables whose distributions are not symmetric. Because high Application of skew distributions، in this paper after a brief review of famous skew distributions، normal، t، skew normal and skew t distributions were fitted on a real data set taken from Mobarakeh Steel Company medical data and then best fit was selected using AIC.

Obesity (OB) is one of the health problems that may lead other diseases. Many risk factors make OB that one of them is working on Shift Work (SW). In the present research, we are going to study the relationship between SW and OB by controlling confounding factor and with use of multilevel modeling, the powerful method for modeling correlated and longitudinal data. The data were extracted is annual observation from workers who worked at Isfahan’s Mobarakeh Steel Factory (ISCF) that collected in health and safety executive between 2001 until 2010 for longitudinal study. In this research we study the effect of SW on OB with controlling blood pressure, age, and education level. MLwiN programmer version 2.1 was used to apply a multilevel modeling. Total person who participate in this study was 6713 with 7 repetitions and range 10. The 45.2%, 6%, 48.8% of participation were day worker, weekly shift worker and routine shift worker respectively. In this study with controlling confounding factor WSW was shown significance relationship with OB (p=0.005) and more result shown decreasing BMI in routine shift worker rather than day worker. Since in most studies SW Mentioned as increasing factor for OB it can be something of a pattern in how the work schedule, pay and bonuses as a suitable model of ISCF can be used to reduce the effect on OB on SW.

High blood pressure (HBP) is one of the effective risk factors for many diseases. Hence, a variety of studies have been done for identifying its risk factors which have led to the diagnosis of different factors, among which working on shift work (WSW) can be mentioned. In this longitudinal study, we deal with the effect of WSW on BP by controlling the confounding factors through GEE regression which is a powerful tool for correlational and longitudinal data analysis. In this retrospective cohort study, data collection was done through annual observations of health and safety executive (HSE) center of Mobarakeh Steel Company (MSCO) of Isfahan on the workers in 2007-2009. For data analysis, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were regarded as dependent variables, whereas body mass index (BMI), age, education level (EL), and shift work were considered independent variables. SPSS version 15 was used to apply GEE regression to the assessment of parameters corresponding to the factors causing change in SBP and DBP. Of the independent variables, BMI and age had a significant relationship with SBP and DBP; however, the results did not indicate any significant relationships between BP and WSW and EL. In this study, there was not a significant relationship between shift work and BP. This can be attributed to the likelihood of SWS being healthier, as well as the flexibility of work hours, income, and more intervals for shift workers in comparison to day workers.