A preliminary study on the association of single nucleotide polymorphisms of interleukin 4 (IL4), IL13, IL4 receptor alpha (IL4Rα) & Toll-like receptor 4 (TLR4) genes with asthma in Indian adults.

Background & objectives: Interleukin 4 (IL4) and IL13 genes are believed to be responsible for inflammation of the airways in asthmatics. These share a common receptor component called IL4Rα which is another potentially important candidate gene linked to asthma phenotypes. Another gene Toll-like receptor 4 (TLR4) might affect the incidence or progression of asthma through the expression of proinflammatory genes. Several single nucleotide polymorphisms (SNPs) in IL4, IL13, IL4Rα and TLR4 have been reported to be linked to asthma or related phenotypes in several ethnic populations using linkage studies and association studies. However, the results have not been consistent. We investigated five SNPs (C-589T and C-33T of IL4, G+2044A of IL13, A+1902G of IL4Rα, and A+896G of TLR4) in patients with adult onset asthma to evaluate their role in manifestation and severity of asthma. Methods: Adult (>18 yr of age) patients with asthma (n=100) and healthy controls (n=50) were included in the study. Genotyping was performed using sequenom MassARRAY technology. Results: The mutant alleles of the C-589T and C-33T SNPs in the promoter region of IL4 were present in 4 per cent patients with asthma but absent from the control group suggesting that the variations in IL4 may contribute to asthma occurrence. The SNPs of other genes were seen in both controls and patients. Interpretation & conclusions: The results suggest the possible association between the genetic distribution of C-589T and C-33T SNPs of IL4 with asthma in Indian adults.

Association of socio-economic status with family history in adult patients with asthma.

Background & objectives: Socio-economic status is associated with increased morbidity in patients with asthma. The aim of the present study was to assess the association between socio-economic status and family history of asthma in adult asthma patients. Methods: The study included 200 adults with asthma and 400 non-asthmatic controls. Socio-economic status was determined based on income. Regression analysis was used to estimate odd ratios in relation to socio-economic class, using age, gender, family history of asthma and smoking habits. Results: The highest occurrence of having any family history of asthma was observed in the high class group (88.2%), followed by upper middle class (79.5%), lower middle class (60%) and the lowest in the low class group (34%). Having any family history of asthma was an important risk factor in both univariate and multivariate analyses in lower middle class, upper middle class and high class, but not in the low class group. Interpretation and conclusions: The results indicated a positive association between having a family history of asthma and higher socio-economic status. Further studies on a large representative sample need to be conducted to confirm these findings.

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.

Factors associated with non-adherence to specific allergen immunotherapy in management of respiratory allergy.

Background. Non-adherence to specific allergen immunotherapy is a major hurdle faced by the allergist, contributing to poor clinical outcomes. Objectives. To assess the independent association of various factors with non-adherence to specific allergen immunotherapy. Methods. Fifty consecutive (non-adherent) and control (adherent) subjects receiving specific allergen immunotherapy were included in the study and various factors related to non-adherence including socio-demographic, clinical and immunotherapy related variables were compared between the two groups by univariate and multivariate analysis. Results. On univariate analysis, gender, allergic conjunctivitis, family history, progression of disease, perception of immunotherapy, medicine requirement, and the pattern of missed doses greater than two in the last 10, 20 and 30 doses were found to be significantly associated with non-adherence. On multivariate analysis, independent association was observed with allergic conjunctivitis, family history, perception of immunotherapy, missed doses greater than two in the last 10 doses of immunotherapy and medicine requirement. Conclusions. The independent factors associated with non-adherence may vary between different settings and countries. There is a need for developing individual case holding programmes to improve clinical outcomes in patients receiving specific allergen immunotherapy.

House dust mite sensitivity is a factor in chronic urticaria.

BACKGROUND: Chronic urticaria is one of the perplexing problems faced by clinicians. There are a few reports associating house dust mite sensitivity with chronic urticaria, based upon the patient's history as well as intradermal skin testing and in vitro analysis. AIMS: To investigate the possible association between house dust mite sensitivity and chronic urticaria. METHODS: In this case control study three groups of patients were enrolled. Group I: Chronic urticaria (73 subjects). Group II: Chronic urticaria with collateral allergic disorders (49 subjects). Group III: Normal subjects without chronic urticaria or other allergies (25 subjects). All the patients underwent skin prick testing with antigens of the house dust mite, Dermatophagoides pteronyssinus (DP) and Dermatophagoides farinae (DF), with positive and negative controls. RESULTS: Among the patients with chronic urticaria, 78/122 (64%) patients had skin sensitivity to house dust mites. Out of these, 39/73 (53%) had chronic urticaria alone and 39/49 (79%) had chronic urticaria with other associated allergies. Among the normal control subjects, 7/25(28%) reacted positively to house dust mites. CONCLUSION: This study suggests a possible association of house dust mite sensitivity with chronic urticaria.