[Comparison of activation pattern of selected trunk muscles during over ground and treadmill walking]

Given the biomechanical differences between over ground and treadmill walking, it is expected that the contraction of muscles should be also different, so exercise training in these scenarios may have various effects on trunk muscles. The aim of this study was to compare amplitude and duration of activation of trunk muscles during over ground and treadmill walking to prescribe a suitable exercise mode considering the special circumstances of each person. Nineteen healthy 20-40 years old male with sedentary life style were selected via simple sampling. Surface electromyography of rectus abdominis, external oblique, longissimus and multifidus muscles were recorded. In each gait cycle, there was not statistically significant differences on duration of trunk muscles activity between treadmill and over ground walking. The mean amplitude of these muscles was greater on treadmill in comparison with over ground and this difference was statistically significant for rectus abdominis [P=0.005], longissimus [P=0.018] and multifidus [P=0.044] muscles. Stabilizing role of trunk muscles during walking causes them to be active throughout the entire gait cycle. The increased muscle amplitude on treadmill might show that more motor units may be recruited during the contraction, which is helpful in prescribing the appropriate type of exercise especially to patients who have trunk muscles weakness

Residential segregation and infant mortality: a multilevel study using Iranian census data

There is a great amount of literature concerning the effect of racial segregation on health outcomes but few papers have discussed the effect of segregation on the basis of social, demographic and economic characteristics on health. We estimated the independent effect of segregation of determinants of socioeconomic status on infant mortality in Iranian population. For measuring segregation, we used generalized dissimilarity index for two group and multi group nominal variables and ordinal information theory index for ordinal variables. Sample data was obtained from Iranian latest national census and multilevel modeling with individual variables at level one and segregation indices measured at province level for socioeconomic status variables at level two were used to assess the effect of segregation on infant mortality. Among individual factors, mother activity was a risk factor for infant mortality. Segregated provinces in regard to size of the house, ownership of a house and motorcycle, number of literate individual in the family and use of natural gas for cooking and heating had higher infant mortality. Segregation indices measured for education level, migration history, activity, marital status and existence of bathroom were negatively associated with infant mortality. Segregation of different contextual characteristics of neighborhood had different effects on health outcomes. Studying segregation of social, economic, and demographic factors, especially in communities, which are racially homogenous, might reveal new insights into dissimilarities in health

[Comparison of nested case-control and cohort analysis methodologies using a district TB registry data]

The nested case-control study has become popular as an efficient alternative to the full-cohort design. This study compares the results of a nested case-control analysis approach with the full cohort analysis. A cohort of 276 subjects [new cases from a TB registry] was used for this study. Cox Regression model was used for the full cohort analysis. In order to do the nested case-control analysis, for each death, three random controls were selected from those who did not suffer from the outcome at the time of the outcome took place. Case control data was analyzed by the conditional logistic regression model. Results from both cohort and nested case-control analyses show that treatment group is the only variable that affects on the outcome. Gender, place of residence, and age has no effect on the outcome. For binary exposure variables with trivial effects [e.g. Gender and place of residence], the relative efficiency of nested case-control study design is approximately 75%. Results of this study show that nested case-control study is not only an easy and cost-effective method for data analysis but also is as robust as cohort analysis in rate ratio and its variance estimation

[Study of the susceptible factor in wife abuse among women referred to karaj forensic medicine center in 2005: a case - control study]

Violence against women, which is seen in most societies, is a concealed social disorder. This social issue in itself gives rise to other health and social problems among its victims. This study attempted to identify the contributing factors in violence against women in Iran by evaluating the cases referred to Karaj Forensic Medicine Center. In this case- control study, a questionnaire was fulfilled for 100 married women who suffered violence at home and referred by the judiciary in 2005 to Karaj forensic medicine center, and also 100 married women who referred to Karaj forensic medicine kenter by the judiciary for reasons other than wife abuse and report no history of violence at home. With increasing age of women and men, wife abuse decreased. There was no significant association between education level of men or women and wife abuse [NS]. Crime history [P < 0.001], polygamy [p < 0.001], religious conviction [p < 0.001] and addiction of husband [p < 0.001] had a significant association with wife abuse. Lower age of woman, addiction of man, and low economic welfare of family of man were independent predictors of wife abuse. In addition, our study revealed that incompatibility of partners, guardianship of a person in family of husband, polygamy, religious conviction of man, violence against children, man job, and history of criminal record are the contributing factors in wife abuse