Likelihood ratios of clinical, laboratory and image data of pancreatic cancer: Bayesian approach

PURPOSE

The diagnosis of pancreatic cancer (PC) is most frequently established in advanced stages. The aim of this study is to estimate the likelihood ratios (LRs) of diagnostic data with regards to PC that could be used to approach an earlier diagnosis.

METHODS

A case-control study of 300 patients - 150 histological diagnosed cases of PC and 150 age-matched controls hospitalized for study of jaundice, abdominal pain, weight loss and/or chronic pancreatitis - was conducted. Bayesian probabilities in the form of LRs were estimated for PC predictions.

RESULTS

Probability of PC was associated with jaundice [odds ratio (OR) 2.89; confidence interval (CI) 1.71-4.85], glycemic disturbance (OR 5.64; CI 2.36-13.46), tobacco index >20 (OR 2.11; CI 1.08-4.09) and tumour marker CA 19-9 (OR 9.33; CI 1.36-63.95). Computed tomography showed the highest test performance with regards to PC when comparing with other diagnostic tests. LRs for variables relevant to PC were estimated, among the most relevant: jaundice LR + 1.92, CA 19-9 LR + 5.36 and computed tomography LR + 4.15. The prediction model with an endoscopic retrograde cholangiopancreatography at a tertiary referral hospital determined a 67% probability of detecting PC.

CONCLUSIONS

Through a Bayesian approach we can combine clinical, laboratory and imaging data to approximate to an earlier diagnosis of PC.

The Tape-Stripping Technique as a Method for Drug Quantification in Skin

Quantification of drugs within the skin is essential for topical and transdermal delivery research. Over the last two decades, horizontal sectioning, consisting of tape stripping throughout the stratum corneum, has become one of the traditional investigative techniques. Tape stripping of human stratum corneum is widely used as a method for studying the kinetics and penetration depth of drugs. This paper shows the applications of the tape stripping technique to quantify drug penetration through the skin, underlining its versatile application in the area of topical and transdermal drugs.

Assessing phytochemical intake in a group of Mexican women

OBJECTIVE

Identify the content of selected phytochemicals (PHYs) in Mexican foods and evaluate the reliability of a food frequency questionnaire (FFQ) in assessing PHYs intake among Mexican women.

MATERIAL AND METHODS

Values for PHYs content were obtained from four different data sets. PHYs intake was assessed in 50 women of reproductive age enrolled in a longitudinal cohort study. Values were obtained from a FFQ administered twice, one year apart in order to evaluate its reliability. Selected PHYs included flavonol (FOL), flavones (FES), flavanol (FAL), secoisolariciresinol (SE), matairesinol (MA), lariciresinol (LA), pinoresinol (PI), cynamic acid (CA) and coumestrol (CU).

RESULTS

Daily PHYs intake ranged from 1.3 microg +/- 0.9 for MA to 116.3 +/- 43.8 mg for CA. The adjusted correlation coefficients ranged from 0.17 for FAL to 0.47 for LA. Pinto beans, oranges, hot sauce, broccoli, apples and onions were the main sources of the selected PHYs daily intake.

DISCUSSION

The results of this study contribute to our understanding of the consumption of PHYs in the Mexican diet, and would help evaluate their potential health impact.

Cervical cancer: a qualitative study on subjectivity, family, gender and health services

Background

In 2002, cervical cancer was one of the leading causes of death in Mexico. Quantitative techniques allowed for the identification of socioeconomic, behavioral and biological characteristics that are part of its etiology.

However such characteristics, are inadequate to explain sufficiently the role that emotions, family networks and socially-constructed categories such as gender play in the demand and utilization of health services for cervical cancer diagnosis and treatment and neither the timely undertaking of preventive actions, such as getting a PAP smear or seeking adequate and continuons treatment.

Methods

A qualitative study was carried out to analyze the role of different social and cultural factors in the timely detection of cervical cancer. As part of a multi-level, multi-method research effort, this particular study was based on individual interviews with women diagnosed with cervical cancer (identified as the "cases"), their female friends and relatives (identified as the "controls") and the cases' husbands.

Results

The results showed that both: denial and fear are two important components that regulate the behavior of both the women and their partners. Women with a small support network may have limited opportunities for taking action in favor of their own health and wellbeing.

Conclusion

Women tend not to worry about their health, in general and neither about cervical cancer in particular, as a consequence of their conceptualizations regarding their body and feminine identify – both of which are socially determined. Furthermore, it is necessary to improve the quality of information provided in health services.

Dietary and genetic determinants of homocysteine levels among Mexican women of reproductive age

OBJECTIVE

To evaluate the independent and joint effects of dietary folate, vitamin B(12) consumption and methylenetetrahydrofolate reductase (MTHFR) polymorphisms (677C>T and 1298A>C) on the circulating folate and homocysteine (Hcy) levels among Mexican women of reproductive age.

DESIGN

A cross-sectional, population-based study.

SUBJECTS

The first 130 healthy non-pregnant women (aged 16-34 years) who agreed to participate in a reproductive cohort in Morelos, Mexico.

MAIN OUTCOME MEASUREMENTS

Dietary intakes of vitamin B(12) and folate were estimated using a semiquantitative food frequency questionnaire. MTHFR 677C>T and 1298A>C polymorphisms were ascertained using the PCR-based method. Serum levels of Hcy and folate were determined using high-performance liquid chromatography and radioimmunoassay, respectively.

RESULTS

Genotype frequencies for the MTHFR 677C>T polymorphism were 21.5% (CC), 52.3% (CT) and 26.2% (TT) among Mexican women. Of the population, 22% had the MTHFR 1298AC genotype, while no individual carried the 1298CC genotype. We observed an increased level of Hcy among carriers of the 677TT genotype, compared to carriers of the 677CC genotype. The highest level of Hcy was observed among MTHFR 677TT carriers with low B(12) intake (<2.0 microg/day), which resulted with a significant interaction (P=0.01).

CONCLUSION

Vitamin B(12) is an important determinant of Hcy levels in Mexico. Supplementation of folic acid with vitamin B(12) may be preferable when the MTHFR 677T variant allele is prevalent.

Applications of thermo-reversible pluronic F-127 gels in pharmaceutical formulations

It is, sometimes, desirable to maintain a constant plasma drug concentration within the therapeutically effective concentration range. The use of high viscosity hydromiscible vehicles such as hydrophilic gels, is one of various approaches for controlled drug delivery, and represents an important area of pharmaceutical research and development. Of these systems, Pluronic F-127 (PF-127) provides the pharmacist with an excellent drug delivery system for a number of routes of administration and is compatible with many different substances. Gels containing penetration enhancers have proven to be especially popular for administering anti-inflammatory medications since they are relatively easy to prepare and very efficacious.

Methylenetetrahydrofolate reductase 677C>T polymorphism and gastric cancer susceptibility in Mexico

This study investigated whether methylenetetrahydrofolate reductase MTHFR 677C>T polymorphism modified gastric cancer (GC) risk independently as well as in combination with folate intake and alcohol consumption. A hospital-based case-control study of 201 cases and 427 controls was conducted in three geographical areas of Mexico, between 1994 and 1996. The MTHFR 677T allele frequency was 51.0% in cases compared with 45.3% in controls. After controlling for dietary sources of folate, alcohol intake and other selected variables, a significant increase in GC risk was found among carriers of the 677TT genotype compared with those with the 677CC genotype (odds ratio (OR) 1.62, 95% confidence interval (CI) 1.00-2.59), with a significant trend (P = 0.048). There were no significant interactions between the MTHFR polymorphism and consumption of folate and alcohol. Our results suggest that the high prevalence of MTHFR 677T allele may be a contributor to the high rate of morbidity and mortality in GC in Mexico.

[Risk factors in invasive cervical cancer among Mexican women]

OBJECTIVE

To evaluate the association between invasive Cervical Cancer (CC) and high risk Human PapillomaVirus (HR-HPV) (viral load and type 16), along with other gynecological and socioeconomic factors.

MATERIAL AND METHODS

Individually matched case-control study (215 women with invasive CC and 420 controls). The study population was recruited between 2000 and 2001. A set of variables traditionally linked with CC (gynecological and socioeconomic factors) and two variables related to HPV infection (viral load and type 16) were assessed. Hybrid Capture II was used to detect HR-HPV DNA. Viral load was measured by light measurements expressed as relative light units (RLU) and they were categorized for analysis into four groups: negative (< 1 RLU), low viral load (1-49 RLU), middle load (50-499 RLU) and high load (>499 RLU). The analysis included univariate, bivariate and multivariate techniques being the final step the estimation of Odds Ratios (OR) by means of conditional logistic regression models. Results. The probability of having invasive CC was 78 times higher in patients with infection of HR-HPV. Risk increases with HPV type 16 (OR = 429.7) as compared with other types of HR-HPV (OR = 64.1). An important trend was observed with the increase of the viral load (from 46.6 with low viral load; to 250.7 with intermediate and 612.9 with high load). The findings also indicate significant diferences in the viral load between cases and controls according to age groups and HR-HPV types (16 versus others high risk types). Finally, the partner-demographic and obstetrical variables related to the disease increased the risk of invasive CC. No association between CC and smoking was observed in this population.

CONCLUSIONS

This study helps in identifying women at higher risk of developing invasive CC as a subset of those patients infected with HR-HPV. The findings point strongly to the importance of the viral load in HR-HPV as a co-factor in the development of this disease. This biomarker contributes to improving the prevention and early detection of this disease and also to identify women at higher risk who carry a high viral load of HR-HPV.

Frequency and Correlates of Adverse Events in a Respiratory Diseases Hospital in Mexico City

OBJECTIVES

To estimate the frequency of severe adverse events (AEs) during hospital stay as well as their type and correlates in a referral hospital for respiratory diseases, using methods similar to those used in the Harvard Medical Malpractice Study.

DESIGN

Retrospective review of medical records in a stratified sample of 836 patients drawn from a total of 4,555 hospital admissions registered during the year 2001.

SETTING

A referral tertiary-care hospital for patients with respiratory diseases located in Mexico City.

MAIN OUTCOME MEASURES

Weighted prevalence of AEs and odds ratios for correlates.

RESULTS

The overall weighted prevalence for AEs was 9.1% (95% confidence interval, 7.5 to 10.4%). Of these patients, 17% had a related transient disability, 52% had a prolonged hospital stay, and 26% had an AE that according to the reviewers contributed to their death. Of the total number of AEs, 74% were qualified as potentially preventable. Among all types of AEs, we identified as most relevant for a chest hospital the delayed surgical treatment of empyema, representing 11% of the total.

CONCLUSIONS

The frequency of AEs in a tertiary-care respiratory hospital is similar to that reported in general hospitals. A strategy to improve the treatment of empyema is needed.

[Breast feeding and the incidence of acute diarrhea during the first three months of life]

OBJECTIVE

To assess the effect of exclusive breastfeeding and its interactions with selected socioeconomic factors, on the incidence of acute infantile diarrhea during the first three months of life.

MATERIAL AND METHODS

A prospective cohort study with a follow up of three months was conducted in 327 mother and child pairs, living in the city of Durango, Mexico, between April and June 1994. Data analyses included simple univariate and bivariate cross-tabulations, as well as multivariate logistic regression models with random effects.

RESULTS

Infants who were not exclusively breastfed were at a significantly increased risk of having acute diarrhea during early infancy (ORcombined breastfeeding=3.23; 95% CI 1.84-5.68 and ORartificial breastfeeding=4.36; 95% CI 2.32-8.19). Moreover, the protective effect of breastfeeding was independent from the effects of the following factors: poor maternal education, lack of social support for baby care, and being an adolescent mother. However, lack of potable water and lack of sewerage were potential effect modifiers of type of lactation deltaG=9.26; p=0.09; ORno water/no sewerage= 2.58; 95% CI 1.10-6.03 in the final multivariate model), for simultaneous lack of potable water and sewerage, which is greater than the sum of the individual OR for each variable.

CONCLUSIONS

Similar to previous studies, exclusive breastfeeding was found to have great importance, since this practice protects the child's health and allows for a better development, despite unfavorable social and economic conditions. In particular, it seems that the protection conferred by breastfeeding is stronger when home conditions are poor, but this same condition presents an intervention opportunity, particularly the assurance of potable water provision for the infant when breastfeeding is not an option.

Helicobacter pylori-CagA seropositivity and nitrite and ascorbic acid food intake as predictors for Gastric Cancer

A hospital-based case-control study was carried out between 1994 and 1996 to evaluate the risk of gastric cancer (GC) according to Helicobacter pylori-CagA (+) seropositivity, nitrite and ascorbic acid intake. Three geographical areas of Mexico were selected on the basis of their contrasting dietary patterns and H. pylori seroprevalence. Nitrite and ascorbic acid consumption were estimated by interview among 211 cases and 454 matched controls. Serum antibodies against IgG H. pylori and CagA were detected by immunosorbent assays. The adjusted risk for GC was significantly higher among CagA+ subjects compared with those that were CagA negative (Odds Ratio (OR)=2.04 95% Confidence Interval (CI) 1.37-3.02 P for trend P < 0.001), this effect remained significant among diffuse GC cases (OR 2.05 95% CI 1.25-3-36). No significant effects due to nitrite and ascorbic consumption or interactions of these nutrients with CagA seropositivity were detected. Seropositivity to H. pylori CagA+ strains may be an independent factor for diffuse GC in Mexico.

Nutritional factors and breast cancer in Mexico

Breast cancer (BC) morbidity and mortality in Mexico are on the rise, affecting younger women with more frequency. Nutritional factors are often mentioned as determinants of BC but their relevance is not well established in Latin-American countries, where dietary habits show great variation. From a study population previously assembled in Mexico City, 141 histologically confirmed cases of BC were matched by age (+/-3 yr) to an equal number of hospital controls. A food frequency questionnaire was administered to all subjects and the risk of BC was estimated in relation to the intake of selected nutrients. The findings of this study show a protective effect against BC due to a high intake of polyunsaturated fat (odds ratio, OR = 0.10, 95% CI = 0.02-0.40, P for trend = 0.001) and vitamin E (OR = 0.10, 95% CI = 0.02-0.44, P for trend = 0.003) among postmenopausal women. In addition, our findings also suggest that a high intake of total fiber (OR = 0.29, 95% CI = 0.08-1.10, P for trend = 0.080) and carotenes (OR = 0.42, 95% CI = 0.16-1.14, P for trend = 0.088) lowers BC risk among premenopausal women. The relationship between the intake of nutrients and BC risk needs further confirmation.

Dichlorodiphenyldichloroethane burden and breast cancer risk: a meta-analysis of the epidemiologic evidence

The relationship of dichlorodiphenyltrichloroethane (DDT) exposure and breast cancer risk has received increasing attention since the beginning of the 1990s. Contradicting published results regarding the relationship between body burden levels of p,p'-dichlorodiphenyldichloroethane (p,p'-DDE)--the main DDT metabolite--and breast cancer, we argue that such differences stem from methodologic differences among those studies. We performed a meta-analysis of 22 articles using DerSimonian and Laird's method for random effects models. The Q-statistic was used to identify heterogeneity in the outcome variable across studies. The gradient of p,p'-DDE exposure in epidemiologic studies was homogenized to serum lipid bases (nanograms per gram). The potential for publication bias was examined by means of the Begg's test. We discuss methodologic features of the studies in an attempt to reconcile the findings. The summary odds ratio (OR) for selected studies was 0.97 (95% confidence interval, 0.87-1.09) and the gradient of exposure ranged from 84.37 to 12,948 ng/g. No overall heterogeneity in the OR was observed (chi-squared = 27.93; df = 23; p = 0.218). Neither the study design nor the lack of breast-feeding control or the type of biologic specimen used to measure p,p'-DDE levels were the causes of heterogeneity throughout the studies. Evidence for publication bias was not found (p = 0.253). Overall, these results should be regarded as a strong evidence to discard the putative relationship between p,p'-DDE and breast cancer risk. Nevertheless, the exposure to DDT during critical periods of human development--from conception to adolescence--and individual variations in metabolizing enzymes of DDT or its derivatives are still important areas to be researched in regard to breast cancer development in adulthood.

Capsaicin consumption, Helicobacter pylori positivity and gastric cancer in Mexico

Gastric cancer (GC) incidence has not declined in Mexico. We assessed whether the intake of capsaicin (CAP), the pungent compound of chili peppers, increases the risk of GC independently of H. pylori positivity (Hp). From 1994 to 1996, a hospital-based case-control study was performed in 3 areas of Mexico; 234 cases of GC and 468 matched controls were enrolled and their diet and other characteristics were inquired. Chili pepper intake was queried by interview and CAP content of chilies was determined in a separate analysis by gas chromatography to estimate CAP intake; IGg Hp serum antibodies were determined by ELISA. The risk of GC was increased (OR = 1.71; 95% CI = 0.76-3.88) among high-level consumers of CAP (90-250 mg of capsaicin per day, approximately 9-25 jalapeño peppers per day) as compared to low-level consumers (0-29.9 mg of capsaicin per day, approximately 0 to less than 3 jalapeño peppers per day; p for trend p = 0.026); this effect was independent of Hp status and other potential GC determinants and was higher among diffuse GC cases (OR = 3.64; 95% CI = 1.09-12.2; p for trend = 0.002) compared to intestinal GC cases (OR = 1.36; 95% CI = 0.31-5.89; p for trend = 0.493). No significant interaction was found between CAP intake and Hp on GC risk. Chili pepper consumption might be an independent determinant of GC in Mexico.

[Factors associated with quality of life parameters in older adults in Morelos]

OBJECTIVE

This study aimed to identify a set of factors related to quality of life across the dimensions of physical, social and emotional functioning and general health perception in an elderly population from the state of Morelos, Mexico.

MATERIAL AND METHODS

A cross-sectional study was carried out from March to September of 1997 in urban and rural areas of the state of Morelos. The sample was built from randomly selected 2,571 households in the study areas. Data for the study were collected by means of structures personal interviews, using a questionnaire applied to 869 subjects who were 60 years or older at the time of the interview. Quality of life was analyzed in four dimensions: physical, social and emotional functioning and general health perception. Independent variables were: gender, age, perceived morbidity, activity level, health check-up and hospitalization during the last year, tobacco consumption and family income. Statistical analyses went from descriptive statistics to the fitting of multivariate unconditional logistic regression models.

RESULTS

The factors associated with the dimensions of quality of life were: physical functioning; gender, illness in last year, age, tobacco consumption and activity level. In social functioning only health check up was significant, as protector factor of good social quality. In emotional functioning the associated factors were: gender, illness and medical check-up in last year. For the dimension health perception the variables were: gender, illness, hospitalization in last year and activity. All of them statistically significant p < 0.05.

CONCLUSIONS

The factors associated with quality of life vary according to each dimension. However; gender, morbidity, health check up and activity were common for the dimensions studied; so that these aspects should be considered for planning interventions to improve the quality of life in elderly people.

Preterm birth in relation to maternal organochlorine serum levels

PURPOSE

To evaluate the associations of serum levels of p,pacute;-DDE and two other persistent organochlorine pesticides, beta-HCH and HCB, in relation to preterm birth.

METHODS

During 1995 we performed a case-cohort study and 233 mothers were recruited at three large maternity hospitals in Mexico City. Serum levels were obtained shortly after delivery.

RESULTS

A non-significant increased risk of preterm birth in relation to serum p,p'-DDE levels was observed. There was also a suggestion of an increased risk of preterm birth among women in the highest tertile of beta-HCH (adjusted odds ratio 1.85, 95% CI = 0.94-3.66, p value for test of trend p = 0.08) compared with the lowest tertile. No association was found between HCB serum levels and preterm births.

CONCLUSIONS

These findings suggest that p,pacute;-DDE and other organochlorine pesticides may pose a risk to preterm birth in countries that continue to use such insecticides for malaria control.

[Evaluation of the availability, utilization, and costs of computerized tomography in the state of Morelos, Mexico]

OBJECTIVE

To assess the availability, utilization, and costs of computerized tomography (CT scan) in private and public hospitals in Morelos State, Mexico.

MATERIAL AND METHODS

From January to April 1999, a cross-sectional study was carried out in two private and two public hospitals in Morelos, Mexico. Individual face-to-face interviews were conducted with directors, managers, radiologists, and heads of maintenance at each hospital. Statistical analysis was performed to describe the variables measuring availability, utilization, and costs of CT scans. A comprehensive assessment of CT scans was also performed. Emphasis was made on the variability of observed patterns among the participating hospitals.

RESULTS

CT scan technology has been used by hospitals in Morelos State for over ten years; programs for preventive or corrective maintenance of these equipments are available, although at high costs. No strategies for technology assessment are available for acquisition of CT scanners nor during their period of utilization. This study did not attempt to evaluate the appropriateness of the clinical use of CT nor its untoward effects.

CONCLUSIONS

Findings from the present study showed that: 1) a lack of mechanisms for technology assessment and management of CT scans prevented hospitals from managing CT scanning technologies efficiently; 2) technology assessment regulation is not available, even though it is necessary for the adequate selection of the best technologies, on the basis of their efficiency, effectiveness, safety, and availability.

Serum levels of beta-hexachlorocyclohexane, hexachlorobenzene and polychlorinated biphenyls and breast cancer in Mexican women

Information on the association between exposure to beta-hexachlorocyclohexane (beta-HCH), hexachlorobenzene (HCB) or polychlorinated biphenyls (PCBs) and the incidence of breast cancer is inconclusive. However, exposure to such compounds is a public health concern in Mexico and is subject to recent regulation. Serum levels of beta-HCH, HCB and PCBs were analysed in 95 histologically confirmed breast cancer cases and 95 hospital controls, 20-79 years of age, from Mexico City, enrolled between March 1994 and April 1996. After adjusting for established risk factors, there was no evidence of a relationship between beta-HCH, HCB and PCBs and breast cancer risk (OR for beta-HCH tertile 3 versus tertile 1: 1.05 95% CI 0.46-2.40; OR for HCB tertile 3 versus tertile 1: 0.46 95% CI 0.20-1.07; OR for PCBs 1.31 95% CI 0.33-5.21 for the high category of exposure). This study lends no support to the case for a role for beta-HCH, HCB or PCBs in breast cancer aetiology.

Food sources of phytoestrogens and breast cancer risk in Mexican women

We analyzed the intake of selected foods that contain phytoestrogens in relation to breast cancer (BC) risk using data from a hospital-based case-control study performed in Mexico City from 1994 to 1995. A total of 198 women with BC, aged 21-79 years, were individually age matched to an identical number of women with no breast disease. By a direct interview, information on socioeconomic characteristics and diet was obtained. A semiquantitative questionnaire was used to estimate the frequency of consumption of 95 foods. The effect of selected foods that contain phytoestrogens on BC risk was estimated using logistic regression models. The adjusted odds ratio for the consumption of more than one slice of onion per day and BC was 0.27 (95% confidence interval = 0.16-0.47), with a statistically significant trend (p < 0.001). This protective effect remained after adjustment for known risk factors of BC. Among premenopausal women, there was also a protective and significant effect due to the intake of lettuce and spinach and nonsignificant protective effects for the consumption of apples and herbal tea. Additional studies aimed at evaluating the potential protective effect of particular phytoestrogens on BC risk are needed.

[Identification of malignant breast lesions in Mexico]

OBJECTIVE

To evaluate the modes of detection of breast malignancies in Mexico City and to estimate the number of patients diagnosed in advanced stages.

MATERIAL AND METHODS

This cross-sectional study was conducted between 1994 and 1996, among 256 women with a histological diagnosis of breast cancer, at three tertiary level public hospitals in Mexico City. Personal interviews were conducted to collect data on reproductive characteristics, clinical history, and breast cancer modes of detection. Data analysis consisted of percentages, odds ratios, and 95% confidence intervals.

RESULTS

Ninety percent of women sought medical care after identifying a breast lump by themselves. Only 10% of patients had a stage-I tumor; all 27 cases first identified by a physician were in stage II-B and higher.

CONCLUSIONS

An increasing trend of breast cancer mortality in Mexico City will persist, unless a greater proportion of tumors in situ is detected; this would require enhancing breast cancer screening programs and conducting an intense educational intervention among women at risk.

[Prevalence of hearing loss and correlated factors in a cement plant]

OBJECTIVE

To assess the impact of occupational exposure to noise, as well as its relationship with other factors that can induce hearing loss.

MATERIAL AND METHODS

In January and February 1997, we conducted sonometry and dosimetry tests in a cement factory, as well as audiometric test in 85 cement workers, to identify sources of noise and evaluate the effect to noise exposure and other factors, of the prevalence of occupational hearing loss. Statistical analysis was conducted using measures of central tendency, bivariate analysis and polynominal regression models.

RESULTS

High noise levels were found in the crushing, crude milling, and cement milling sites. The highest individual dose corresponded to the packer job post. Fifty-five per cent of the study population presented some degree of hearing loss due to noise exposure. The cement processing area with the highest percentage of damaged workers was calcination.

CONCLUSIONS

Our results show that noise is a serious risk factor in particular sites of cement factories, and also that an elevated number of hearing loss cases are due to occupational noise exposure in this industry; Our findings underscore the need for designing and implementing hearing protection programs, to assure the health and safety of cement workers.