Inhaled Marijuana and the Lung.

Although vaping has recently increased as a mode of inhaling marijuana and has been associated with numerous and sometimes fatal cases of acute severe lung injury, smoking remains the most common method of inhaling marijuana and has been studied more extensively. Smoking marijuana has been shown to produce modest but significant short-term bronchodilation both in healthy subjects and in those with asthma. Long-term effects of habitual marijuana smoking include the following: (1) symptoms of chronic bronchitis (increased cough, sputum production, and wheezing); (2) modest effects on lung function in cross-sectional studies (no significant decrease in FEV1 but mild reductions in FEV1/forced vital capacity ratio, an increase in forced vital capacity and other lung volumes, reductions in specific airway conductance, and variable effects of maximal midexpiratory flow rates and diffusing capacity); and (3) variable effects on age-related decline in FEV1 in longitudinal studies. Most cohort and case-control studies have failed to show that marijuana smoking is a significant risk factor for lung cancer despite the presence of procarcinogenic components in marijuana smoke, although further study is warranted. The question whether marijuana smoking is associated with asthma is unclear and requires further investigation. Although delta-9 tetrahydrocannabinol, the principal psychoactive component of marijuana, has immunomodulatory properties that hypothetically could increase the risk of pneumonia, the few available studies in marijuana smokers have failed to find an increased risk of pneumonia in immunocompetent users, although effects in immunosuppressed individuals have been variable.

Sleep Quality and Nocturnal Symptoms in a Community-Based COPD Cohort.

Small studies have suggested that patients with chronic obstructive pulmonary disease (COPD) have poor sleep quality. Our aim was to examine the prevalence of subjective sleep-related complaints and predictors of poor sleep quality in a large community-based COPD cohort. We analyzed cross-sectional data on sleep questionnaire responses from the Canadian Cohort of Obstructive Lung Disease (CanCOLD) study, a population-based, prospective longitudinal cohort study across Canada. The cohort comprises a COPD group and two matched non-COPD (never-smokers and ever-smokers) groups. Sleep-related symptoms were assessed using questionnaires including Pittsburgh Sleep Quality Index (PSQI). A total score of PSQI > 5 is indicative of poor sleep quality. Health-related quality of life measures and the presence of mood disturbance were assessed using Short Form-36™ Health Survey (SF-36) multi-item questionnaires and Hospital Anxiety and Depression Scale (HADS), respectively. Predictors of poor sleep quality were analyzed using multivariable logistic regression analysis. Of the 1123 subjects, 263 were healthy controls, 323 at-risk controls, and 537 had COPD (297 had mild, 240 with moderate to severe disease). The mean PSQI score was not significantly different between groups. COPD patients with poor sleep quality had lower diffusion capacity, higher HADS anxiety and depression scores and lower SF-36 mental and physical component summary scores than COPD patients classified as good sleepers. The presence of restless legs and obstructive sleep apnea symptoms, waist circumference, predicted diffusion capacity and HADS anxiety and depression scores were identified as independent predictors of poor sleep quality.

The impact of comorbidities on productivity loss in asthma patients.

BACKGROUND: Health-related productivity loss is an important, yet overlooked, component of the economic burden of disease in asthma patients of a working age. We aimed at evaluating the effect of comorbidities on productivity loss among adult asthma patients. METHODS: In a random sample of employed adults with asthma, we measured comorbidities using a validated self-administered comorbidity questionnaire (SCQ), as well as productivity loss, including absenteeism and presenteeism, using validated instruments. Productivity loss was measured in 2010 Canadian dollars ($). We used a two-part regression model to estimate the adjusted difference of productivity loss across levels of comorbidity, controlling for potential confounding variables. RESULTS: 284 adults with the mean age of 47.8 (SD 11.8) were included (68 % women). The mean SCQ score was 2.47 (SD 2.97, range 0-15) and the average productivity loss was $317.5 per week (SD $858.8). One-unit increase in the SCQ score was associated with 14 % (95 % CI 1.02-1.28) increase in the odds of reporting productivity loss, and 9.0 % (95 % CI 1.01-1.18) increase in productivity loss among those reported any loss of productivity. A person with a SCQ score of 15 had almost $1000 per week more productivity loss than a patient with a SCQ of zero. CONCLUSIONS: Our study deepens the evidence-base on the burden of asthma, by demonstrating that comorbidities substantially decrease productivity in working asthma patients. Asthma management strategies must be cognizant of the role of comorbidities to properly incorporate the effect of comorbidity and productivity loss in estimating the benefit of disease management strategies.

Dietary and supplemental antioxidant and anti-inflammatory nutrient intakes and pulmonary function.

OBJECTIVE: A limited but growing body of evidence supports a significant role of antioxidant and anti-inflammatory micronutrients in pulmonary health. We investigated the associations of dietary and supplemental intakes of vitamins A, C, E and D, Se and n-3 PUFA with pulmonary function in a population-based study. DESIGN: Population-based, cross-sectional study and data analysis of fruits and vegetables, dairy products and fish, vitamins A, C, E and D, Se and n-3 PUFA supplemental intakes, pulmonary risk factors and spirometry. SUBJECTS: Chinese older adults (n 2478) aged 55 years and above in the Singapore Longitudinal Ageing Studies. RESULTS: In multiple regression models that controlled simultaneously for gender, age, height, smoking, occupational exposure and history of asthma/chronic obstructive pulmonary disease, BMI, physical activity, and in the presence of other nutrient variables, daily supplementary vitamins A/C/E (b = 0·044, SE = 0·022, P = 0·04), dietary fish intake at least thrice weekly (b = 0·058, SE = 0·016, P < 0·0001) and daily supplementary n-3 PUFA (b = 0·068, SE = 0·032, P = 0·034) were individually associated with forced expiratory volume in the first second. Supplemental n-3 PUFA was also positively associated with forced vital capacity (b = 0·091, SE = 0·045, P = 0·045). No significant association with daily dairy product intake, vitamin D or Se supplements was observed. CONCLUSIONS: The findings support the roles of antioxidant vitamins and n-3 PUFA in the pulmonary health of older persons.

Curcumins-rich curry diet and pulmonary function in Asian older adults.

BACKGROUND: Research on the effects of dietary nutrients on respiratory health in human populations have not investigated curcumin, a potent anti-oxidant and anti-inflammatory compound present principally in turmeric used in large amounts in Asian curry meals. OBJECTIVES: To examine the association of curry intake with pulmonary function among smokers and non-smokers. DESIGN: The frequency of curry intake, respiratory risk factors and spirometry were measured in a population-based study of 2,478 Chinese older adults aged 55 and above in the Singapore Longitudinal Ageing Studies. RESULTS: Curry intake (at least once monthly) was significantly associated with better FEV(1) (b = 0.045±0.018, p = 0.011) and FEV(1)/FVC (b = 1.14±0.52, p = 0.029) in multivariate analyses that controlled simultaneously for gender, age, height, height-squared, smoking, occupational exposure and asthma/COPD history and other dietary or supplementary intakes. Increasing levels of curry intake ('never or rarely', 'occasional', 'often', 'very often') were associated with higher mean adjusted FEV(1) (p for linear trend = 0.001) and FEV(1)/FVC% (p for linear trend = 0.048). Significant effect modifications were observed for FEV(1) (curry* smoking interaction, p = 0.028) and FEV(1)/FVC% (curry*smoking interaction, p = 0.05). There were significantly larger differences in FEV(1) and FEV(1)/FVC% between curry intake and non-curry intake especially among current and past smokers. The mean adjusted FEV(1) associated with curry intake was 9.2% higher among current smokers, 10.3% higher among past smokers, and 1.5% higher among non-smokers. CONCLUSION: The possible role of curcumins in protecting the pulmonary function of smokers should be investigated in further clinical studies.

Co-morbid association of depression and COPD: a population-based study.

OBJECTIVES: Depression occurs commonly among patients with COPD, but the independent association of depression and COPD and the effect of depression on COPD outcomes are not well established. METHOD: A population sample of 2402 Chinese aged >or=55 with and without COPD (characteristic symptoms of chronic cough, sputum or breathlessness and airflow obstruction and FEV(1)/FVC<0.70) was assessed on Geriatric Depression Scale (score>or=5), dependence on basic activities of daily living (ADL), SF-12 health status, smoking and medication behaviour. RESULTS: The 189 respondents with COPD showed higher depressive symptoms prevalence (22.8%) than 2213 respondents without COPD (12.4%); multivariate odd ratio (OR) was 1.86; 95% CI, 1.25-2.75 after controlling for confounding risk factors. In multivariate analyses of respondents with COPD, those who were depressed (N=43), compared to those who were not (N=146), were more likely to report ADL disability (OR=2.89, p=0.049) poor or fair self-reported health (OR=3.35, p=0.004), poor SF-12 PCS scores (OR=2.35, p=0.041) and SF-12 MCS scores (OR=4.17, p<0.001). CONCLUSION: Depressive symptoms were associated with COPD independent of known risk factors. In COPD participants, depressive symptoms were associated with worse health and functional status and self-management.

Depressive symptoms and chronic obstructive pulmonary disease: effect on mortality, hospital readmission, symptom burden, functional status, and quality of life.

BACKGROUND: Depressive symptoms are common among patients with chronic obstructive pulmonary disease (COPD), but depression's impact on COPD outcomes has not been fully investigated. We evaluated the impact of comorbid depression on mortality, hospital readmission, smoking behavior, respiratory symptom burden, and physical and social functioning in patients with COPD. METHODS: In this prospective cohort study, 376 consecutive patients with COPD hospitalized for acute exacerbation were followed up for 1 year. The independent associations of baseline comorbid depression (designated as a Hospital Anxiety and Depression Scale score of > or =8) with mortality, hospital readmission, length of stay, persistent smoking, and quality of life (determined by responses to the St George Respiratory Questionnaire) were evaluated after adjusting for potential confounders. RESULTS: The prevalence of depression at admission was 44.4%. The median follow-up duration was 369 days, during which 57 patients (15.2%) died, and 202 (53.7%) were readmitted at least once. Multivariate analyses showed that depression was significantly associated with mortality (hazard ratio, 1.93; 95% confidence interval, 1.04-3.58), longer index stay (mean, 1.1 more days; P = .02) and total stay (mean, 3.0 more days; P = .047), persistent smoking at 6 months (odds ratio, 2.30; 95% confidence interval, 1.17-4.52), and 12% to 37% worse symptoms, activities, and impact subscale scores and total score on the St George Respiratory Questionnaire at the index hospitalization and 1 year later, even after controlling for chronicity and severity of COPD, comorbidities, and behavioral, psychosocial, and socioeconomic variables. CONCLUSIONS: Comorbid depressive symptoms in patients with COPD are associated with poorer survival, longer hospitalization stay, persistent smoking, increased symptom burden, and poorer physical and social functioning. Interventions that reduce depressive symptoms may potentially affect COPD outcomes.

Frequent hospital readmissions for acute exacerbation of COPD and their associated factors.

OBJECTIVE: The factors that determine frequent hospital readmissions for acute exacerbations of COPD (AECOPD) are poorly understood. The aim of this study was to ascertain rates of re-hospitalizations for AECOPD patients and evaluate factors associated with frequent readmissions for acute exacerbations. METHODS: We conducted a cross-sectional survey of 186 patients with moderate to severe COPD with one or more admissions for acute exacerbations to two large general hospitals. Frequency of previous readmissions for AECOPD in the past year, and clinical characteristics, including depression and spirometry were ascertained in the stable state both before discharge and at 1-month post discharge. RESULTS: Among them, 67% had one or more previous readmission, 46% had two or more, 9% had 10-20 readmissions in the 1-year period prior to current admission. There was a high prevalence of current or ex-heavy smokers, underweight patients, depression and consumption of psychotropic drugs, and low prevalence of caregiver support, pulmonary rehabilitation and influenza and pneumococcal vaccination. Univariate analysis showed that male sex, duration >5 years, FEV(1) < 50% predicted, use of psychotropic drugs, receipt of pulmonary rehabilitation and vaccination were significantly associated with frequent past readmissions. Multivariate analysis revealed that disease duration >5 years (odds ratio (OR) = 2.32; 95% confidence interval (CI): 1.09-4.92), FEV(1) < 50% predicted (OR = 2.60; 95% CI: 1.18-5.74), use of psychotropic drugs (OR = 13.47; 95% CI: 1.48-122.92) and vaccination status (OR = 3.27; 95% CI: 1.12-9.57) were independently associated with frequent readmissions for AECOPD. CONCLUSION: Frequent past readmission for AECOPD was associated with disease severity and psychosocial distress and increased use of vaccinations.

Prevalence and determinants of excessive daytime sleepiness in an Asian multi-ethnic population.

BACKGROUND AND PURPOSE: To investigate the prevalence and determinants of daytime sleepiness in an Asian multi-ethnic population. Cross-sectional survey based on a questionnaire in multi-ethnic Asian adult population of Singapore (2.4 million). PATIENTS AND METHODS: Measured frequency of excessive daytime sleepiness (EDS), socio-demographic status, sleep duration, perceived sleep insufficiency, frequent awakenings, difficulty falling asleep, snoring, breathing pauses, GHQ-12, shift work, solvent exposure at work, substance use, medications, and chronic diseases in random sample of 2,298 adults, aged 20-74 years, representing Chinese, Malays and Indians. RESULTS: Among the respondents, 10.8% reported usually feeling sleepy in the daytime, and 9.0% were classified as having EDS. Marked ethnic difference was observed, with higher rates of EDS in Malays and Chinese, compared to Indians. Increased risk of EDS was associated with perceived sleep insufficiency; snoring and breathing pauses; shift work and solvent exposure at work; psychiatric morbidity and chronic diseases, particularly chronic rhinitis; and medications with sedating effects. CONCLUSIONS: Daytime sleepiness is associated with a multiplicity of highly prevalent risk factors in the community, including sleep behavior, breathing-, work- and medically related factors. Significant ethnic differences, which were not explained by these factors, were observed between Chinese, Malays and Indians.

Craniofacial morphology, head posture, and nasal respiratory resistance in obstructive sleep apnoea: an inter-ethnic comparison.

The aim of this study was to measure craniofacial morphology and nasal respiratory resistance (NRR) in Malay, Indian and Chinese subjects with obstructive sleep apnoea (OSA). The sample consisted of 34 male subjects, 27-52 years of age (Malay n = 11, which included five mild and six moderate-severe OSA; Indian n = 11, which included six mild and five moderate-severe OSA; and Chinese n = 12, which included six mild and six moderate-severe OSA) diagnosed using overnight polysomnography. After use of a decongestant, NRR was recorded using anterior and posterior rhinomanometry. Standardized lateral cephalometric radiographs were used to record linear and angular dimensions. Malay subjects with moderate-severe OSA had a shorter maxillary (sp-pm) and mandibular (gn-go) length when compared with a mild OSA reference sample (P < 0.05). The hyoid bone was located more caudally in the Chinese moderate-severe subjects (hy-NL, hy-ML)(P < 0.05), and may be a useful diagnostic indicator for severity in this racial group. No pattern of differences for NRR was seen between the moderate-severe and mild OSA subjects. The consistently lower values for nasopharyngeal resistance in all the moderate-severe subjects when compared with the mild group may indicate that some compensation at this level of the airway had taken place. Strong positive correlations between craniocervical angulation (NL/OPT) and total airway resistance and the turbulent component of flow (k(2)) suggest that head posture is sensitive to fluctuations in airway resistance (P < 0.01).

The E237G polymorphism of the high-affinity IgE receptor beta chain and asthma.

BACKGROUND: The beta chain of high-affinity IgE receptor (FcepsilonRI beta) has been proposed as a candidate gene for asthma and atopic diseases. OBJECTIVES: To determine the prevalence of the E237G polymorphism of the FcepsilonRI beta gene and to investigate its association with asthma and total IgE levels in 3 Asian populations. METHODS: A total of 291 asthmatic patients (141 Chinese, 68 Malay, and 82 Indian) and 355 asymptomatic blood donors (157 Chinese, 100 Malay, and 98 Indian) were recruited. The E237G genotype was determined by allele-specific polymerase chain reaction. Total serum IgE level was measured by enzyme-linked immunosorbent assay. RESULTS: The G allele was more common in Chinese controls (17.9%) than in Malay (11.5%) (P = .05) and Indian (9.2%) (P = .01) controls. Genotypes with the G allele were more prevalent in asthmatic patients in the Chinese population (odds ratio, 1.97; 95% confidence interval, 1.05-3.77; P = .04). CONCLUSIONS: There were interethnic differences in the frequencies of the G variant among Chinese, Malay, and Indian populations. The E237G polymorphism of FcsRI beta may be a risk factor for asthma in the Chinese population.

Trends and ethnic differences in COPD hospitalization and mortality in Singapore.

STUDY OBJECTIVE: COPD mortality alone among major causes of diseases continues to rise in most countries worldwide. We examine trends, and gender and ethnic differences in COPD hospitalization and mortality in Singapore from 1991 to 1998, and examine possible explanations. DESIGN: Analysis of population-based health administrative data. SETTING: Multi-ethnic (Chinese, Malay and Indian) population of Singapore (3 million population). METHOD: Data on hospitalizations and deaths due to COPD as the underlying cause (ICD codes 491, 492, 496), extracted from national databases, were used to calculate age-specific and standardized rates for the population aged 55 + years. COPD accounted for 4.6% of total deaths (5.8% in those aged 55 +), and 1.02% of all hospitalizations (3.1% in those aged 55 +). RESULTS: COPD mortality in 1998 decreased steeply by -43.7% from 1991 (a decline that continued a steady trend since 1970), while hospitalization showed little significant change (-3.3%). Men had 4 and 5 times higher mortality and hospitalization, and also showed less favorable trends than women. Malays, especially males, showed the highest level and least favorable decline of mortality. CONCLUSION: Exceptionally steady declines in COPD mortality rates, and stable rates of hospitalization are observed in Singapore in the 1990s. Differing levels and trends of hospitalization and mortality by gender and ethnicity are related to known demographic variations and trends of smoking prevalence in the country.

Diet, reproductive factors and lung cancer risk among Chinese women in Singapore: evidence for a protective effect of soy in nonsmokers.

The factors associated with risk of lung cancer among nonsmokers have not been fully elucidated, but dietary factors have consistently been shown to play a role. Chinese women are unique in having a high incidence of lung cancer despite a low smoking prevalence. This population is also known to have a high intake of soy, a dietary source of phytoestrogens. We conducted a hospital-based case-control study among Singapore Chinese women, comprising 303 cases and 765 age-matched controls, of whom 176 cases and 663 controls were lifetime nonsmokers. Data on demographic background, reproductive factors and dietary intake of fruit, vegetables and soy foods were obtained by in-person interview. We observed an inverse association between intake of total, cruciferous and non-cruciferous vegetables and risk of lung cancer among smokers. Although smokers in the highest tertile of fruit intake also had a lower risk, this was not statistically significant. Higher intake of soy foods significantly reduced risk of lung cancer among lifetime nonsmokers, but not among smokers. When soy isoflavonoid intake in mg/week was computed based on frequency and portion size of intake of eight common local soy foods, the adjusted OR among nonsmokers for the highest tertile compared to the lowest was 0.56, 95% CI 0.37-0.85 (p for trend <0.01). Fruit intake was also significantly associated with reduced lung cancer risk among nonsmokers, but the effect was not significant after adjustment for soy intake. On the other hand, soy intake remained an independent predictor of risk after controlling for fruit intake. Reproductive effects were also primarily confined to lifetime nonsmokers, among whom having 3 or more livebirths (adjusted OR 0.65, 0.44-0.96) and a menstrual cycle length of more than 30 days (OR 0.46, 0.25-0.84) accorded a significantly reduced risk of lung cancer. Place of birth was significantly associated with risk among nonsmokers (OR 2.6, 1.7-3.9 for China-born vs. local born) but not among smokers. When analysis was restricted to nonsmokers with adenocarcinomas, the dietary effects were consistent or enhanced. On stepwise regression, soy intake and cycle length emerged as the independent dietary and reproductive predictors of lung cancer risk in nonsmokers. These findings are consistent with other evidence suggesting an involvement of estrogen-related pathways in lung cancer among non-smoking women.