Journal of School of Public Health and

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A case-control study was undertaken to determine risk factors for malnutrition in Hormozgan Province, which has the highest child malnutritionrateinthiscountry.Thestudy subjects were 6-to 30-month old children living on the outskirts of Bandar Abbas. Cases consisted of 158 children having weight-for-age Z scores under -1 by NCHS/WHO standards, controls were 258 subjects with scores over -1. Physical and anthropometrical examinations were performed and mothers interviewed for personal history and various socioeconomic variables. There was no matching procedure, but sex and age distributions were similar in the two groups. Parental education level was significantly lower in cases than controls (P=0.005) and cases were also more likely to have a history of acute disease (OR=1.66, CI%95 1.07-2.57). While father's occupational status differed somewhat between the two groups (P-0.083), other social and demographic factors such as family size, age difference between siblings, mother's occupation plus vaccination history, parent smoking habits, and the use of day-care facilities were distributed similarly between cases and controls. Early supplemental feeding (P=0.0384) and frequent health check-ups (PO.000) were found to protect against growth retardation. The link between child growth, parental education and regular health monitoring emphasizes the importance of addressing non-nutritional factors in the fight against malnutrition.

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Hearing loss is a controversial occupational disease in fire fighters because exposure to hazardous levels of noise in this job is so variable and unpredictable. In this study, audiometric assessments were performed on 117 fire fighters to evaluate their hearing loss. The results showed that the average fire fighter has a characteristic noise-induced threshold shift, with maximum hearing loss occurring at 6000 Hz. The hearing loss at the test frequencies was related to age, although the association exceeded that of general population only in 6000 Hz frequency in left ear (p=0.021). Despite finding a pattern of threshold shift typical of occupational hearing loss, it must be noted that after controlling for age, there was no strong relation between length of time on the job and the degree of hearing loss. It seems that more extensive studies are needed to evaluate this relationship.

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Background and Aim: Case-Control studies provide evidence in the area of health. Validity and accuracy of such studies depend to a large extent on the similarity (similar distributions) of the case and control groups according to confounding variables. Matching is a method for controlling or eliminating the effects of important confounders. Matching using propensity score has recently been introduced to control the effect of confounders, especially when there are many of them in a study.

Materials and Methods: Matching according to propensity score was used in a genetic association study-a case-control study involving 300 subjects-to assess the effect of candidate genes on Alzheimer's disease in the Iranian population. Propensity score was calculated using STATA.8 software age, sex, education level, job and genetic background were included in the model to calculate the score.

Results: A total of 385 blood samples were taken from the participants. We managed to extract DNA in 155 of the 173 case subjects and in 161 of the 212 control subjects. The model for propensity score was statistically significant. Of the total of 316 DNA samples, 302 were matched based on their calculated propensity scores, while the individual matching method could only deliver 28 pairs.

Conclusion: The propensity-score matching method results in selection of a larger number of pairs, as compared with the conventional individual matching method. We propose to use this method, which also ensures a similar distribution of confounders between the case and control groups, particularly when there are limitations in the number of subjects available for matching.

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Background and Aim: Amblyopia is an important cause of weak vision and blindness. A preliminary study on validity of the current screening program in Shahrood City's kindergartens showed that this method may not be efficient enough, especially because of low sensitivity and referral problems. We tried to compare efficiencies and costs of screening by trained staff and optometrists in detecting patients.

Materials and Methods: We conducted a cost-effectiveness analysis using the decision-tree method. We replaced nurses with optometrists to compare costs per detected case by the two screening methods. The number of detected cases and costs per each detected case are compared. Also, the cost-effectiveness of four criteria screening examinations (with different validities) used by optometrists was estimated.

Results: Costs per case detected by optometrists and by current screening methods were 270000 and 556000 Rails (Rs), respectively (with baseline examination criteria and 6.4% prevalence). With a lower prevalence of amblyopic patients, CER (cost-effectiveness ratio) will increase in both methods, but the increase in the current screening method is less than the optometric method. In the optometrist method, avoidable costs and savings per detected case vary from 250000 Rs at a prevalence of 7.4% to 1185000 Rs at a prevalence of 1.4%. Sensitivity analysis showed that costs of "monitoring of screening" in the optometrists method and costs of "follow up in the current screening method" have strong effects on CER CER will decrease by 9.6% and 15%, respectively, if this costs decrease to 25%.

Conclusion: The cost, per detected case, of screening amblyopia by optometrists in kindergartens is half that by the current method. In areas with a low prevalence, the efficiency of screening by using optometrists increases remarkably.