Haplotype analysis of ADAM33 polymorphisms in asthma: A pilot study

Background & objectives: ADAM33 is implicated as a potentially strong candidate gene for asthma and bronchial hyper-responsiveness. Many polymorphisms of ADAM33 have been studied along with ADAM33 expression in various cells of the lungs. Haplotype analysis also showed association with asthma in different populations across the world. Therefore, the aim of this study was to perform a comprehensive screening of ADAM33 polymorphisms in adult patients with asthma. Methods: Thirty five polymorphisms of ADAM33 were genotyped in 55 patients with asthma and 53 controls. The association of single nucleotide polymorphisms (SNPs) and haplotypes with phenotypes of asthma was analysed. Results: The genotype, minor allele frequency, odds ratio and Hardy–Weinberg equilibrium did not show any significant difference among cases and controls. No association was found between SNPs of ADAM33 with the severity of asthma. Correlation analysis of ADAM33 SNPs to the phenotypes, based on clinical variables and allergen sensitization, did not show significant difference. Haplotype analysis showed that rs2280090 and rs2280091 were associated with asthma in the patient group. Interpretation & conclusions: Haplotype analysis showed an association of the two SNP variations with asthma. These SNPs lead to amino acid change and are prone to phosphorylation, which may affect expression levels and protein function of ADAM33 and asthma susceptibility.

Identification of a threshold for biomass exposure index for chronic bronchitis in rural women of Mysore district, Karnataka, India.

Background & objectives: Exposure to air pollution due to combustion of biomass fuels remains one of the significant risk factors for chronic respiratory diseases such as chronic bronchitis. There is a need to identify the minimum threshold level of biomass index that is significantly associated with chronic bronchitis. This study was undertaken to identify a threshold for biomass exposure index in a rural women population in Mysore district, south India. Methods: A cross-sectional survey was conducted in a representative population of Mysore and Nanjangud taluks. Eight villages each from Mysore and Nanjangud were randomly selected based on the list of villages from census 2001. A house-to-house survey was carried out by trained field workers using the Burden of Obstructive Diseases questionnaire, which evaluated the biomass smoke exposure and chronic bronchitis. All the women aged above 30 yr were included in the study. Results: A total of 2011 women from Mysore and 1942 women from Nanjangud participated in the study. All women were non-smoking and used biomass fuels as the primary fuel for cooking. A threshold of biomass fuel exposure of 60 was identified on multivariate analysis in Mysore district after adjusting for age, passive smoking and working in a occupational exposure to dust, as the minimum required for a significant association with chronic bronchitis. One in every 20 women in Mysore district exposed to biomass fuel exposure index of 110 or more developed chronic bronchitis. Interpretation & conclusions: The minimum threshold of biomass exposure index of 60 is necessary to have a significant risk of developing chronic bronchitis in women. The number needed to harm to develop chronic bronchitis reduces with increasing biomass exposure index and women residing in rural Nanjangud have a higher risk for developing chronic bronchitis as compared to women in Mysore.

Factors affecting 30-month survival in lung cancer patients.

Background & objectives: Age adjusted incidence rate of lung cancer in India ranges from 7.4 to 13.1 per 100,000 among males and 3.9 to 5.8 per 100,000 among females. The factors affecting survival in lung cancer patients in India are not fully understood. The current study was undertaken to evaluate the factors affecting survival in patients diagnosed with lung cancer attending a tertiary care cancer institute in Bangalore, Karnataka, India. Methods: Consecutive patients with primary lung cancer attending Bangalore Institute of Oncology, a tertiary care centre at Bangalore, between 2006 and 2009 were included. Demographic, clinical, radiological data were collected retrospectively from the medical records. Results: A total of 170 consecutive subjects (128 males, 42 females) diagnosed to have lung cancer; 151 non-small cell lung cancer (NSCLC) and 19 small cell lung cancer (SCLC) were included. A higher proportion of never-smokers (54.1%) were observed, mostly presenting below the age of 60 yr. Most subjects were in stage IV and III at the time of diagnosis. More than 50 per cent of patients presented with late stage lung cancer even though the duration of symptoms is less than 2 months. The 30-month overall survival rates for smokers and never-smokers were 32 and 49 per cent, respectively. No significant differences were observed in 30 month survival based on age at presentation, gender and type of lung cancer. Cox proportional hazards model identified never-smokers and duration of symptoms less than 1 month as factors adversely affecting survival. Interpretation & conclusions: Our results showed that lung cancer in Indians involved younger subjects and associated with poorer survival as compared to other ethnic population. Studies on large sample need to be done to evaluate risk factors in lung cancer patients.

Prevalence of chronic cough, chronic phlegm & associated factors in Mysore, Karnataka, India.

Background & objectives: Chronic cough and chronic phlegm are important indicators of respiratory morbidity, accelerated lung function decline, increased hospitalization and mortality. This study was planned to estimate the prevalence of chronic cough and phlegm in the absence of dyspneoa and wheezing and to study its associated factors in a representative population of Mysore district. Methods: A cross-sectional survey was planned in a representative population of Mysore taluk. Eight villages were randomly selected based on the list of villages from census 2001. Trained field workers using the Burden of Obstructive Diseases questionnaire carried out a house-to-house survey. Results: A total of 4333 adult subjects were enrolled in the study with 2333 males and 2000 females. The prevalence of chronic cough in the community was 2.5 per cent and that of chronic phlegm was 1.2 per cent. A significant association was observed between chronic cough and age, gender, occupation and smoking and chronic phlegm with age, gender, occupation, indoor animals and smoking. A multivariate analysis confirmed independent association of age, occupation and smoking for chronic cough and age and smoking for chronic phlegm. On sub-group analysis of males, heavy smokers had higher prevalence of chronic cough and chronic phlegm as compared to light smokers and non smokers. Interpretation & conclusions: The prevalence of chronic cough was 2.5 per cent and chronic phlegm was 1.2 per cent in the general population in Mysore which is lower than that observed in other studies. Heavy smoking was an important preventable risk factor identified in this study and efforts towards smoking cessation are crucial to achieve good respiratory health in the community.

Inheritance patterns, consanguinity & risk for asthma.

Background & objectives: Family history is an important risk factor for the development of asthma, contingent upon genetic and environment interaction. Since there is paucity of data on asthma inheritance in Indian population, the present study was undertaken to investigate the inheritance patterns of asthma and the effect of family history and consanguineous marriage on asthma inheritance. Methods: A total of 200 families, 100 index children and 100 index adults with clinically diagnosed asthma, along with 400 non-asthmatic children and adults as controls were selected for the present study. Information about the family history of each patients and controls was collected and analyzed pedigrees were also constructed. Results: A history of asthma in any member of the family was observed in 44.5 per cent of cases and 5.3 per cent of controls (P < 0.001). A differential risk of developing asthma was noted in family history of asthma in different first and second degree relatives of children and adult patients. Consanguineous marriage was also noted in parents in 24.5 per cent of cases and 12.3 per cent of controls (P< 0.001). The most common mode of asthma inheritance was recessive. Interpretation & conclusions: Our results showed that consanguineous marriage and family history of asthma are important determinants in the development of asthma in the offspring.

Ruptured hydatid cyst of lung.

We report a case of 26 year old woman who had ruptured hydatid cyst of the right lung. The chest radiograph and CT features were suggestive of a ruptured hydatid cyst with detached and collapsed endocyst within the exocyst. Intraoperatively communication between cyst and bronchus could be demonstrated. Interesting CT appearance and demonstrable communication of cyst with bronchus is the reason for this case report.