The association between maternal anemia during pregnancy and preterm birth.

BACKGROUND & AIMS: Maternal anemia is one of the most serious health problems during pregnancy. The causes of anemia include iron deficiency, parasitic diseases, micronutrient deficiencies, and hereditary hemoglobinopathies. Because the reported association between maternal anemia and preterm labor in different studies is varied depending on the month of pregnancy this study aims to determine this relationship after adjustment for potential confounders. METHODS: A case-control study was conducted among 801 pregnant women (267 cases and 534 controls) in Sardashat, Iran from October 2012 to October 2013. Hemoglobin (Hb) values were measured for all women participating in the study during the first and second trimesters of pregnancy, and the average Hb values were presented. Statistical analyzes were performed with logistic regression. RESULTS: The mean age of participants was 26.4 ± 5.25 years for the case group and 27.2 ± 6.51 years for the control group. Preterm birth was associated with maternal anemia during pregnancy [aOR = 2.69 (95% CI; 1.46 to 4.95)] even after adjusting for confounding effects including maternal age, history of abortion [aOR = 2.41 (95% CI; 1.42 to 4.08)], history of preterm birth [aOR = 11.38 (95% CI; 3.48 to 37.22)], obesity (aOR: 3.441; CI95%: 1.18-10.06), parity [aOR = 0.42 (95% CI; 0.25 to 0.69)], preeclampsia/eclampsia [aOR = 6.08 (95% CI; 2.64 to 14)], and GDM [aOR = 4.80 (95% CI; 2.02 to 11.41)]). CONCLUSION: Early detection and adequate treatment of anemia during pregnancy can help reduce the prevalence of preterm birth.

Adult ADHD screening scores and hospitalization due to pedestrian injuries: a case-control study.

BACKGROUND: The aim of this study was to investigate the association between adult ADHD screening scores and hospitalization due to pedestrian injuries in a sample of Iranian pedestrians. METHODS: Through a case-control study, a case population of 177 pedestrians injured by the vehicles in road traffic crashes were compared with 177 controls who lacked a record of intentional or unintentional injuries enrolled from various wards of Imam Reza University Hospital which is a specialty teaching hospital located in the same city with similar referral level. The cases and controls had an age range of 18-65 years and were matched on gender and age. ADHD symptom profile was assessed using the Persian Self-report Screening Version of the Conner's Adult ADHD Rating Scales (CAARS-S:SV). The association of ADHD screening score and pedestrian injuries was investigated using multiple binary logistic regression to investigate the independent effect of ADHD index score on belonging to case group. Both crude and adjusted odds ratios were reported. RESULTS: Men comprised 86.4% of the study subjects. The crude odds ratios for all the four ADHD subscales to be associated with pedestrian injuries were 1.05, 1.08, and 1.04 for the subscales A (attention deficit), B (hyperactivity/impulsiveness) and ADHD index respectively. However, the association for subscale A was not statistically significant with a borderline p-value. The final multivariate analysis showed that variables associated with pedestrian injuries in the road traffic crashes were ADHD Index score (OR = 1.06, 95% CI: 1.01-1.12); economic status (including household income and expenditure capacity); educational level and total walking time per 24 h. CONCLUSIONS: Adult ADHD screening score can predict pedestrian injuries leading to hospitalization independently from sex, age, economic status, educational level and pedestrian exposure to traffic environment (average walking time).

Motorcyclist risky riding behaviors and its predictors in an Iranian population.

BACKGROUND: Motorcyclist's behavior plays an important role in increasing the mortality rate caused by traffic crash. Identifying the risky behaviors of motorcycle riders is essential to maintain and improve the health of motorcycle riders and other community members. The aim of this study was to determine the riding patterns and risky riding behaviors of motorcycle riders in Bukan as a marginal small-sized Kurdish populated district in North-West of Iran and investigating some predictors of it. METHODS: In this cross-sectional, 340 motorcycle riders of Bukan were studied. By referring to city health center and preparing the city map, the entire city was divided into 14 clusters based on the areas covered by the health centers. Then, 7 clusters were randomly selected out of these 14 clusters. Motorcycle riding behavior questionnaire (MRBQ) was used to study the risky behaviors of motorcycle riders while riding. Both bivariate and multivariate regression analysis methods were used to study the associations. RESULTS: All participants were male. Their mean age was 30.2 (SD=9.1). The most common risky behaviors possessed by at least 23% of motorcycle riders included 1) inappropriate control of motorcycle when turning, 2) taking another person without helmet by motorcycle, 3) riding without helmet, 4) taking more than one person by motorcycle, 5) exceeding the permissible speed outer city, 6) exceeding the permissible speed inside the city and 7) carrying heavy load by motorcycle. Mean normalized MRBQ score was 30.5 (SD=11.2). Based on multivariate analysis, age, lacking a riding license, riding experience and average amount of riding were the independent predictors of risky riding score. CONCLUSIONS: Among the predictive factors that led to high risk behaviors in the studied motorcyclists were low age, marital status, low driving experience, low education, non-use of safety equipment lack of certification. This can be done by increasing drivers' awareness of laws and regulations and promoting the culture of traffic safety to prevent high-risk behaviors in motorcyclists in order to prevent possible injuries.

Manifestation of hemispheric laterality in chewing side preference and handedness.

Introduction: Humans manifest a behavioral inclination towards more utility of one side of the body, in relation with the dominant hemisphere of the brain. The current investigation assessed handedness together with chewing preference which have not been evaluated in various food textures before. Methods: Nineteen young and healthy volunteers chewed hard (walnut) and soft (cake) foods, during surface electromyography recording from masseter muscles. The side of the first and all chews in the two food types were determined and compared with the side of the dominant hand. Results: Results indicated the two lateralities in the same side considerably (60%-70%), implying the solidarity in the control of the dominant hemisphere of the brain. The unilaterality was more prominent in the assessment of all chews in hard food, with higher statistical agreement and correlation. Conclusion: Thereupon masticatory preference is found with probable origins in the dominant hemisphere of the brain.

Evaluating the relationship between adult attention-deficit/hyperactivity disorder and riding behavior of motorcyclists.

BACKGROUND: Motorcycling is one of the main causes of injury, and motorcyclists are vulnerable to road traffic injuries. Attention Deficit Hyperactivity Disorder (ADHD) in adults is presumably one of the determinants of road traffic injuries and motorcyclists' risky behavior. Despite the few studies on the relationship between motorcycle injuries and adult ADHD, their association has not been investigated using standardized instruments. This study aimed to analyze the relationship between motorcyclists' adult ADHD and risky riding behaviors. METHODS: This community-based, cross-sectional study was performed on 340 motorcyclists in Bukan city, west Azerbaijan province, Iran in 2015 and 2016 using a cluster-random sampling in seven areas of the city. According to the city map used by Bukan's Health Centers, the city was divided into 14 clusters. Then, seven clusters (out of 14) were selected randomly. To reach the anticipated sample size, the data were collected from these seven clusters. In this study, the data collection instruments were: standard Motorcycle Rider Behavior Questionnaire (MRBQ), Conners' Adult ADHD Rating Scales (CAARS) questionnaire and a checklist designed by the researchers. The Stata 13 software package was used to analyze the collected data. Pearson correlation coefficient and multiple linear regression were performed to study the linear relationship between ADHD screening and MRBQ scores. RESULTS: All 340 participants were male and the mean age was 30.2 years (SD=9.1). In addition, 22.1% of motorcyclists had a history of motorcycle crash. Bivariate analysis showed a significant association between risky riding behaviors and age, motorcycling records, and mean of riding hours per day (P-value less than 0.05). Multivariate analysis confirmed the correlation between ADHD and risky riding behaviors in all subscales (A, B, D) (p less than 0.05). CONCLUSIONS: Those with a high ADHD screening score are more likely to have risky riding behaviors.

Correction: The short Persian version of motorcycle riding behavior questionnaire and its interchangeability with the full version.

[This corrects the article DOI: 10.1371/journal.pone.0201946.].

The short Persian version of motorcycle riding behavior questionnaire and its interchangeability with the full version.

The aim of current study was to develop a valid and reliable short motorcycle riding behavior questionnaire (SMRBQ) and assess its interchangeability with the original 48-item tool. Through a psychometric study in Bukan district of Iran in 2015, the most recent available Persian version of the motorcycle riding behavior questionnaire (MRBQ) was used as a reference to develop its short version, the SMRBQ. The preliminary version was prepared through expert reviews, and its dimension was further reduced through principal component analysis (PCA). An exploratory factor analysis (EFA) was then applied on the remaining items and the final version was developed with 23 items. The validity, consistency, agreement and interchangeability of the SMRBQ were assessed in parallel with the MRBQ using several statistical methods including Kendall's Tau, intra-class correlation coefficient (ICC), Bland-Altman plot and receiver operating characteristics (ROC) curve analysis. All the 340 participants were males. The mean age of the participants was 30.2 (SD = 9.1). SMRBQ was developed including 23 items. The mean normalized score for the full version was 30.5 (SD = 11.2) and it was 30 (SD = 13.9) for the short version. There was a high correlation between the normalized scores of MRBQ and SMRBQ (Kendall's Tau = 0.82). The ICC of the interchangeability of the full version and short version scales was as high as 0.92 (95% CI: 90.2-93.5). The scale had adequate internal consistency based on the calculated Cronbach's alpha which was 0.85 for the scale. Bland-Altman and ROC curve analysis confirmed the interchangeability and criterion validity of the SMRBQ. The Persian version of SMRBQ was found to be a valid, reliable and feasible tool for assessing motorcycle riding behavior in the studied population.

The Epidemilogical Characteristics of Motorcyclists Associated Injuries in Road Traffics Accidents; A Hospital-Based Study.

OBJECTIVES: To determine the epidemiology of injuries of the motorcyclists in road traffic accidents (RTIs) between 2008 and 2014 in East Azarbayejan province of Iran. METHODS: A cross-sectional study was performed in East Azerbaijan province in Imam Reza hospital on motorcyclists subjected to injuries in RTIs between 2008 and 2014. Demographic characteristics (age, sex), duration of hospitalization, final status of injured people after discharge from the hospital, admission ward, number of admissions due to injuries in RTIs, nature of injury, and the clinical services provided to injured people were gathered from hospital information system (HIS). Demographic characteristics (age, sex), duration of hospitalization, final status of injured people after discharge from the hospital, admission ward, number of admissions due to injuries in RTIs, injured site of the body, nature of injury, and the clinical services provided injured people were gathered from HIS. Standardized data collection form was used for uniform handling of the data. RESULTS: Most of the victims (94.4%) were male. The most frequent injuries pertained to the age group of 18-30 with 1676 (51.4%) injuries. Head, abdomen, lower back, lumbar spine, and pelvis, were the most common injured sites, respectively. Reduction of fracture and dislocation and cranial puncture were the most common provided services. The lowest survival time belonged to the age group over 60 years old. CONCLUSION: Injuries to the head are the most prevalent injuries among motorcyclists in RTIs. So it is suggested that proper interventions be implemented to ensure wearing helmet by motorcyclist and pillion passengers.

Quality of life in epileptic patients compared with healthy people.

BACKGROUND: Epilepsy is a common chronic neurological disorder that has a great impact on people's lives. Patients with epilepsy are at increased risk for poor Quality of Life (QoL). The objective of this study was to evaluate the QoL of epileptic patients in comparison to healthy persons. METHODS: This cross-sectional study was conducted on 52 epileptic patients from Golbu region in Neyshabur (a city in northeast of Iran). Using Short Form Health Survey (SF-36) scale, the data were collected between April and Jun 2012. Every patient were compared with two healthy persons. Epileptic and healthy persons were similar for age, sex and local residence. Pearson's correlation coefficient and t-independent test applied for data analysis through SPSS v. 16 software. RESULTS: Of 52 epileptic patients, 24 were female (46.2%) and 28 were male (53.8%). The mean±SD age of epileptic patients was 40.92±20.33yr (Rang: 15-86yr). The total mean score of SF- 36 in patient group was 55.88 and in healthy group 68.52and this difference was statistically significant (p<0.001). Among the different subscales of SF-36 in epileptic patients, the highest and the lowest mean scores were found for social functioning and general health subscales, respectively. The mean scores in patient group in comparison to healthy group were lower in all subscales of SF-36 and these differences were statistically significant in all domains (except role limitations due to physical problems domain and role limitations due to emotional problems domain). CONCLUSION: The study showed that epilepsy disease has an important role in QoL of patients, thus some interventional programs are necessary to improve their QOL.

Spatial and non-spatial determinants of successful tuberculosis treatment outcomes: An implication of Geographical Information Systems in health policy-making in a developing country.

This retrospective study aimed to address whether or to what extent spatial and non-spatial factors with a focus on a healthcare delivery system would influence successful tuberculosis (TB) treatment outcomes in Urmia, Iran. In this cross-sectional study, data of 452 new TB cases were extracted from Urmia TB Management Center during a 5-year period. Using the Geographical Information System (GIS), health centers and study subjects' locations were geocoded on digital maps. To identify the statistically significant geographical clusters, Average Nearest Neighbor (ANN) index was used. Logistic regression analysis was employed to determine the association of spatial and non-spatial variables on the occurrence of adverse treatment outcomes. The spatial clusters of TB cases were concentrated in older, impoverished and outskirts areas. Although there was a tendency toward higher odds of adverse treatment outcomes among urban TB cases, this finding after adjusting for distance from a given TB healthcare center did not reach statistically significant. This article highlights effects of spatial and non-spatial determinants on the TB adverse treatment outcomes, particularly in what way the policies of healthcare services are made. Accordingly, non-spatial determinants in terms of low socio-economic factors need more attention by public health policy makers, and then more focus should be placed on the health delivery system, in particular men's health.

Development and Psychometric Evaluation of a Socioeconomic Status Questionnaire for Urban Households (SESIran): The Preliminary Version.

BACKGROUND: The aim of present study was to develop and validate an appropriate socioeconomic status (SES) assessment questionnaire to be used through health studies in Iranian urban households. METHODS: The study was conducted through a mixed method study design in Tabriz, northwest of Iran in 2014. It was conducted in several stages including: development of initial version, qualitative study, feasibility evaluation, and assessment of the validity as well as the reliability. The internal consistency, test-retest reliability, content validity, concurrent validity and construct validity were assessed. RESULTS: With respect to the assessment of construct validity, 5 domains (factors) were extracted includ-ing: main factor (α=0.84), self-evaluation of expenditure capacity (α=0.96), wealth (α=0.70), home and furniture (α=0.66) and costs related to health (α=0.55). Intraclass correlation coefficient was above 0.6 for all factors except for wealth domain. CONCLUSION: The questionnaire developed appeared to be a valid and reliable SES assessment tool. It may be of value to be used not only as a complementary questionnaire in most health surveys or clini-cal studies, but also as a main questionnaire in health equity and health economics research.

Effects of antibiotic consumption on children 2-8 years of age developing asthma.

OBJECTIVES: Antibiotic exposure in children is a possible contributor to the increasing asthma prevalence in several countries. The present study aimed to investigate the association between antibiotic exposure and the risk of developing childhood asthma at 2-8 years of age. METHODS: A case-control study was undertaken among children aged 2-8 years old between March and September 2010 in the Urmia district in the northwest of Iran. The cases were doctor-diagnosed asthmatic children based on Global Initiative for Asthma criteria (n=207), and the controls were children without respiratory symptoms (n=400) selected by frequency matching by age and gender. Clinical data including antibiotic exposure was collected by a validated and reliable questionnaire, which was completed by interviewing parents/guardians. RESULTS: Antibiotic consumption during the first year of life increased the odds ratio [OR] of asthma symptoms at 2-8 years of age (crude OR, 2.26; 95% confidence interval [CI], 1.53-3.35; p<0.01), and the strength of association was similar after adjusting for a family history of asthma or atopic disorder, preterm delivery, birth order, and delivery method (adjusted OR, 1.91; 95% CI, 1.27-2.88; p=0.03). CONCLUSIONS: Our study suggests that antibiotic consumption in children was associated with an increased risk of childhood asthma, and an additional confirmative study is needed.

Comparison of three methods in improving bag mask ventilation.

INTRODUCTION: Increasedlife expectancy in populations has brought along specific new scenarios in the fields of medicine for the elderly; prevalence of physical complications such as edentulism and patients with dentures is growing. Management of anesthesia and ventilation in this group of patients has turned into a great challenge. Some researchers suggest dentures to be left in place during bag-mask ventilation; yet, no unanimous agreement exists in this regard. METHODS: In a single blind randomized clinical trial, we studied 300 patients with ASA class I, II (American Society of Anesthesiologists), Mallampati class (I, II) and aged over 55 years in three groups. After induction of anesthesia, in group G dentures were removed and in each buccal space an eight-layer 10 × 10 cm gauze and an oral airway were placed. In group D, the dentures and an oral airway were left in place. In group C (control), after removing dentures just an appropriate oral airway was placed. Then, each three group underwent bag-mask ventilation. Success of bag-mask ventilation (BMV) was considered as increase in end-tidal carbon dioxide to more than 20 mmHg and back to baseline with fresh gas flow of 3 L/min and adjustable pressure limiting valve pressure of 20 cm H2O. Success rates were evaluated between groups. RESULTS: Effective BMV was possible in 91 (91%), 64 (64%) and 41 (41%) patients in groups G, D and C respectively. The differences were statistically significant. Successful BMV rate was significantly higher in female patients in group G compared to group C; 43/44 versus 25/46 individuals, P = 0.0001, odds ratio = 0.03, 95% confidence interval (0.00, 0.22). CONCLUSIONS: Leaving dentures in place in edentulous patients after inducing anesthesia improves bag-mask ventilation. However, placing folded compressed gauze in buccal space leads to more significant improvement in BMV compared to leaving dentures in place.

Why do some pregnant women prefer cesarean delivery in first pregnancy?

BACKGROUND: The increasing number of cesarean section is a great concern in many countries. In Iran cesarean section rate has been steadily rising from 35% in 2000 to 40% in 2005. Preferences for cesarean are often associated with some factors. OBJECTIVE: To investigate factors associated with preference for cesarean delivery, with special emphasis on pregnant women's preferences in first pregnancy in Neyshabur (Northeast of Iran). MATERIALS AND METHODS: In this cross-sectional study, written questionnaires were completed via face to face interview with 797 pregnant women in first pregnancy. Socio-demographic data, preference toward mode of delivery and factors associated with it were assessed by applying questionnaire. Univariate and multivariate analysis were performed to identify the independent variables associated with preference for cesarean delivery. RESULTS: In this study observed that 18.6% of pregnant women preferred caesarean delivery in first pregnancy. The mean age of pregnant women that they preferred cesarean delivery was upper than pregnant women that they preferred vaginal delivery and this difference was statistically significant (p=0.006). There was a statistically significant relation between preference for cesarean delivery and the following variables: educational level (p<0.001), gestational age (p=0.003) spouse's age of pregnant women (p=0.001), physician's advice (p<0.001), and fear of delivery (p<0.001). CONCLUSION: The results of this study show that the majority of pregnant women do not prefer caesarean delivery to vaginal delivery. Nevertheless the preference rate for cesarean delivery exceeded 15% that suggested by WHO and most important factors in pregnant women prefer cesarean deliveries are fear of delivery and physician's advice.

Chewing side preference in first and all mastication cycles for hard and soft morsels.

Preferred chewing side is a still controversial matter and various methods used have yielded some inconsistencies. The aim of this study is to compare the preference determined in different conditions. Nineteen healthy subjects were offered hard (walnut) and soft (cake) foods, while the electromyography was recorded from their masseter muscles, in 2009 in the Research Center of Physical Medicine and Rehabilitation, Tabriz University of Medical Sciences, Tabriz, Iran. Four occurrences were determined as the side of the first chews/all chews in the two food types, and then analyzed for correlations and agreements. For hard food 73.68% and for soft food 57.89% of the subjects showed preference. The comparison of all chews showed a highly significant preference towards the right side in both food types (p=0.000 & 0.003). There was both correlation and agreement between the first chew preferences in both food types, and an agreement between the first and all chew preferences in the hard food. Therefore, there seems to exist some laterality in mastication, which is more explicit when using hard food and assessing all chews.

Emergency department patient satisfaction survey in Imam Reza Hospital, Tabriz, Iran.

INTRODUCTION: Patient satisfaction is an important indicator of the quality of care and service delivery in the emergency department (ED). The objective of this study was to evaluate patient satisfaction with the Emergency Department of Imam Reza Hospital in Tabriz, Iran. METHODS: This study was carried out for 1 week during all shifts. Trained researchers used the standard Press Ganey questionnaire. Patients were asked to complete the questionnaire prior to discharge. The study questionnaire included 30 questions based on a Likert scale. Descriptive and analytical statistics were used throughout data analysis in a number of ways using SPSS version 13. RESULTS: Five hundred patients who attended our ED were included in this study. The highest satisfaction rates were observed in the terms of physicians' communication with patients (82.5%), security guards' courtesy (78.3%) and nurses' communication with patients (78%). The average waiting time for the first visit to a physician was 24 min 15 s. The overall satisfaction rate was dependent on the mean waiting time. The mean waiting time for a low rate of satisfaction was 47 min 11 s with a confidence interval of (19.31, 74.51), and for very good level of satisfaction it was 14 min 57 s with a (10.58, 18.57) confidence interval. Approximately 63% of the patients rated their general satisfaction with the emergency setting as good or very good. On the whole, the patient satisfaction rate at the lowest level was 7.7 with a confidence interval of (5.1, 10.4), and at the low level it was 5.8% with a confidence interval of (3.7, 7.9). The rate of satisfaction for the mediocre level was 23.3 with a confidence interval of (19.1, 27.5); for the high level of satisfaction it was 28.3 with a confidence interval of (22.9, 32.8), and for the very high level of satisfaction, this rate was 32.9% with a confidence interval of (28.4, 37.4). CONCLUSION: The study findings indicated the need for evidence-based interventions in emergency care services in areas such as medical care, nursing care, courtesy of staff, physical comfort and waiting time. Efforts should focus on shortening waiting intervals and improving patients' perceptions about waiting in the ED, and also improving the overall cleanliness of the emergency room.

Parental risk factors of childhood acute leukemia: a case-control study.

BACKGROUND: Leukemia is the most common cancer in children, accounting for near to half of all childhood cancers. Different risk factors might be effective in the occurrence of this cancer such as parental characteristics. This study was done in West Azarbaijan Province in order to determine the relation between parental characteristics and acute leukemia in children. METHODS: This matched case-control study was conducted on children less than 15 years affected by acute leukemia from March 20, 2003 to March 20, 2009. Two control groups were selected, one from hospital and the other from the study population. Cases and controls were matched on age and sex. Logistic regression model was used for data analysis. RESULTS: This study was done on 130 patients, 108 (83.1%) were affected by Acute Lymphoblastic Leukemia and 22 (16.9%) by Acute Myeloblastic Leuke-mia. Seventy two of the patients were male (55.4%) and 58 were female (44.6%). There was a statistically significant correlation between acute leuke-mia and variables such as mother's education [OR=4.2, 95% CI: 2.42, 7.34], mother's history of using Oral Contraceptive Pills [OR=1.77, 95% CI: 1.05, 2.82] and parental relationship [OR=2.05, 95% CI: 1.30, 3.23]. CONCLUSION: It seems that some parental characteristics have an important role in etiology of childhood leukemia.

Do bullae and emphysema increase risk of pneumothorax in silicosis?

BACKGROUND: The occurrence of occupational lung diseases is decreasing due to improvements in occupational health in recent years; however, silicosis and its complications remain important occupational health problems. We have studied the role of emphysema and bullae as predictive factors of secondary spontaneous pneumothorax in acute and accelerated silicosis. METHODS: This study was carried out using questionnaire items on occupational history and conventional computed tomography of lungs. Differences between two groups (silicosis with and without secondary spontaneous pneumothorax) in terms of age, interval of exposure-diagnosis and therefore silica exposure duration were assessed by independent t-test. Fisher's exact test was used to determine the association between secondary spontaneous pneumothorax and both emphysema and bullae. RESULTS: We found a significant association between secondary spontaneous pneumothorax and bullae in acute and accelerated silicosis. CONCLUSION: Pneumothorax in silicosis could be attributed to previous bullae.

Do bullae and emphysema increase risk of pneumothorax in silicosis?

BACKGROUND: The occurrence of occupational lung diseases is decreasing due to improvements in occupational health in recent years; however, silicosis and its complications remain important occupational health problems. We have studied the role of emphysema and bullae as predictive factors of secondary spontaneous pneumothorax in acute and accelerated silicosis. MATERIALS AND METHODS: This study was carried out using questionnaire items on occupational history and conventional computed tomography of lungs. Differences between two groups (silicosis with and without secondary spontaneous pneumothorax) in terms of age, interval of exposure-diagnosis and therefore silica exposure duration were assessed by independentt -test. Fisher's exact test was used to determine the association between secondary spontaneous pneumothorax and both emphysema and bullae. RESULTS: We found a significant association between secondary spontaneous pneumothorax and bullae in acute and accelerated silicosis. CONCLUSION: Pneumothorax in silicosis could be attributed to previous bullae.