[Analysis of clinical characteristics of persistent HBeAg positivity in patients with chronic hepatitis B treated with nucleos(t)ide analogues]

Objective: To explore the clinical characteristics of persistent HBeAg positivity in patients with chronic hepatitis B treated with nucleos(t)ide analogues. Methods: A retrospective analysis was performed according to different data types. An independent sample t-test, Mann-Whitney U test, chi-square test, or Fisher's exact probability method were used. Chronic hepatitis B patients followed up for four years were collected from the follow-up case database of the Department of Infectious Diseases of Zhongshan Third Hospital from January 2009 to December 2018 and were divided into two groups, A and B, with 87 and 145 cases respectively, according to the duration of HBeAg-negativity≤ 3 and persistent positivity >3 years. Statistical analysis was conducted on the age, gender, family history, baseline, follow-up visit duration, liver function, and other data among the two patient groups. Results: There were no statistically significant differences in gender, age, family history of liver cirrhosis, family history of liver cancer, liver cirrhosis condition before treatment, fatty liver disease combined condition before treatment, baseline HBsAg, anti-HBc, alanine aminotransferase, albumin, or total bilirubin between the two groups of patients (P > 0.05). HBV DNA and HBeAg were significantly higher in group B than those in group A at baseline, with P≤0.001. Aspartate aminotransferase and γ-glutamyl transferase were significantly higher in group A than those in group B at baseline. The proportion of family history of hepatitis B was significantly higher in group B (69.0%) than that in group A (50.6%) among the two groups of patients, and the difference was statistically significant (P = 0.005). The proportion of mothers with hepatitis B was significantly higher in group B (25.5%) than in group A (11.5%), P = 0.010. During the treatment process, the HBV DNA quantification was significantly higher in group B than that in group A at 0.5 and 1 years (P≤0.002). The proportion of HBV DNA <100IU/ml was also significantly different at six months and one year (χ(2)=30.327, P < 0.001 and χ(2)=11.779, P = 0.001). The HBsAg level was higher in group B than that of group A in the second and fourth years, P < 0.05. During the entire treatment process, the HBeAg level was significantly higher in group B than that in group A (P < 0.001). A total of seven cases developed liver cirrhosis or cancer during follow-up, including three cases in group A and four cases in group B (P > 0.05). Conclusion: HBeAg-positive patients with chronic hepatitis B have persistent HBeAg positivity when treated with long-term nucleos(t)ide analogues. Accordingly, a greater proportion of this kind of patient family and mothers have a remarkable history of hepatitis B and a reduced HBV DNA relapse rate in the early stages (within a year or less).

Association between toxic drug events and encephalopathy in British Columbia, Canada: a cross-sectional analysis

BACKGROUND

Encephalopathy can occur from a non-fatal toxic drug event (overdose) which results in a partial or complete loss of oxygen to the brain, or due to long-term substance use issues. It can be categorized as a non-traumatic acquired brain injury or toxic encephalopathy. In the context of the drug toxicity crisis in British Columbia (BC), Canada, measuring the co-occurrence of encephalopathy and drug toxicity is challenging due to lack of standardized screening. We aimed to estimate the prevalence of encephalopathy among people who experienced a toxic drug event and examine the association between toxic drug events and encephalopathy.

METHODS

Using a 20% random sample of BC residents from administrative health data, we conducted a cross-sectional analysis. Toxic drug events were identified using the BC Provincial Overdose Cohort definition and encephalopathy was identified using ICD codes from hospitalization, emergency department, and primary care records between January 1st 2015 and December 31st 2019. Unadjusted and adjusted log-binomial regression models were employed to estimate the risk of encephalopathy among people who had a toxic drug event compared to people who did not experience a toxic drug event.

RESULTS

Among people with encephalopathy, 14.6% (n = 54) had one or more drug toxicity events between 2015 and 2019. After adjusting for sex, age, and mental illness, people who experienced drug toxicity were 15.3 times (95% CI = 11.3, 20.7) more likely to have encephalopathy compared to people who did not experience a drug toxicity event. People who were 40 years and older, male, and had a mental illness were at increased risk of encephalopathy.

CONCLUSIONS

There is a need for collaboration between community members, health care providers, and key stakeholders to develop a standardized approach to define, screen, and detect neurocognitive injury related to drug toxicity.

Drug overdose and the risk of cardiovascular diseases: a nested case-control study

BACKGROUND

North America has been experiencing an unprecedented epidemic of drug overdose. This study investigated the associations of drug overdose with the risk of cardiovascular disease (CVD) and 11 major CVD subtypes.

METHODS

This nested case-control study was based on a cohort of 20% random sample of residents in British Columbia, Canada, who were aged 18-80 years and did not have known CVD at baseline (n = 617,863). During a 4-year follow-up period, persons who developed incident CVD were identified as case subjects, and the onset date of CVD was defined as the index date. For each case subject, we used incidence density sampling to randomly select up to five control subjects from the cohort members who were alive and did not have known CVD by the index date, were admitted to an emergency department or hospital on the index date for non-CVD causes, and were matched on age, sex, and region of residence. Overdose exposure on the index date and each of the previous 5 days was examined for each subject.

RESULTS

This study included 16,113 CVD case subjects (mean age 53 years, 59% male) and 66,875 control subjects. After adjusting for covariates, overdose that occurred on the index date was strongly associated with CVD [odds ratio (OR), 2.9; 95% confidence interval (CI), 2.4-3.5], especially for arrhythmia (OR, 8.6; 95% CI, 6.2-12.0), ischemic stroke (OR, 5.3; 95% CI, 2.0-14.1), hemorrhagic stroke (OR, 3.1; 95% CI, 1.2-8.3), and myocardial infarction (OR, 3.0; 95% CI, 1.5-5.8). The CVD risk was decreased but remained significantly elevated for overdose that occurred on the previous day, and was not observed for overdose that occurred on each of the previous 2-5 days.

CONCLUSIONS

Drug overdose appears to be associated with increased risk of cardiovascular diseases.

Spatial-temporal trends in the risk of illicit drug toxicity death in British Columbia

Abstract

Background

Illicit drug poisoning (overdose) continues to be an important public health problem with overdose-related deaths currently recorded at an unprecedented level. Understanding the geographic variations in fatal overdose mortality is necessary to avoid disproportionate risk resulting from service access inequity.

Methods

We estimated the odds of fatal overdose per event from all cases captured by the overdose surveillance system in British Columbia (2015 - 2018), using both conventional logistic regression and Generalized Additive Models (GAM). The results of GAM were mapped to identify spatial-temporal trends in the risk of fatal overdose.

Results

We found that the odds of fatal overdose were about 30% higher in rural areas than in large urban centers, with some regions reporting odds 50% higher than others. Temporal variations in fatal overdose revealed an increasing trend over the entire province. However, the increase occurred earlier and faster in the Interior and Northern regions.

Conclusion

Rural areas were disproportionately affected by fatal overdose; lack of access to harm reduction services may partly explain the elevated risk in these areas.

Risk of cardiovascular diseases in relation to substance use disorders

BACKGROUND

Substance use disorder (SUD) has become increasingly prevalent worldwide, this study investigated the associations of SUD and alcohol, cannabis, opioid, or stimulant use disorder with cardiovascular disease (CVD) and 11 major CVD subtypes.

METHODS

This study was based on a 20% random sample of residents in British Columbia, Canada, who were aged 18 - 80 years at baseline on January 1, 2015. Using linked administrative health data during 2010 - 2014, we identified people with various SUDs and prevalent CVDs at baseline, and examined the cross-sectional associations between SUDs and CVDs. After excluding people with CVDs at baseline, we followed the cohort for 4 years to identify people who developed incident CVDs, and examined the longitudinal associations between SUDs and CVDs.

RESULTS

The cross-sectional analysis at baseline included 778,771 people (mean age 45 years, 50% male), 13,279 (1.7%) had SUD, and 41,573 (5.3%) had prevalent CVD. After adjusting for covariates, people with SUD were 2.7 (95% confidence interval [CI], 2.5 - 2.8) times more likely than people without SUD to have prevalent CVD. The longitudinal analysis included 617,863 people, 17,360 (2.8%) developed incident CVD during the follow-up period. After adjusting for covariates, people with SUD were 1.7 (95% CI, 1.6 - 1.9) times more likely than people without SUD to develop incident CVD. The cross-sectional and longitudinal associations were more pronounced for people with opioid or stimulant use disorder.

CONCLUSIONS

People with SUD are more likely to have prevalent CVD and develop incident CVD compared with people without SUD.

Risk of overdose-related death for people with a history of incarceration

BACKGROUND AND AIMS

Reported associations between previous incarceration and the risk of overdose-related death are substantially heterogeneous, and previous studies are limited by an inability to control for confounding factors in risk assessment. This study investigated the associations of overdose-related death with previous incarceration and the number or cumulative duration of previous incarcerations, and individual or neighborhood characteristics that may potentially modify the associations.

DESIGN AND SETTING

A cohort study using a 20% random sample of residents in British Columbia, Canada.

PARTICIPANTS

A total of 765 690 people aged 23 years or older at baseline as of 1 January 2015. Mean age was 50 years; 49% were males.

MEASUREMENTS

Previous incarcerations that occurred during the 5-year exposure period (January 2010 to December 2014) were identified using provincial incarceration records. Overdose-related deaths that occurred during the 3-year follow-up period (January 2015 to December 2017) were identified using linked administrative health data. Baseline individual and neighborhood characteristics were retrieved from the provincial health insurance data.

FINDINGS

In the cohort, 5743 people had an incarceration history during the exposure period, and 634 people died from drug overdose during the follow-up period. The mortality rate was 897 and 22 per 100 000 person-years for people who did and did not have an incarceration history, respectively. After adjusting for baseline individual and neighborhood characteristics (without any interaction term), people who had an incarceration history were 4.04 times (95% confidence interval 3.23-5.06) more likely to die from drug overdose compared with people without an incarceration history. The association was stronger for females, people without diagnoses of substance use disorder and people without dispensation of opioids for pain or benzodiazepines (P < 0.001 for each interaction term). There was no discernible linear trend between the number or cumulative duration of previous incarcerations and the risk of overdose-related death.

CONCLUSIONS

Previous incarceration appears to be a major risk factor for overdose-related death.

Provincial Overdose Cohort: Population Data Linkage During an Overdose Crisis

IntroductionIn 2016, the Provincial Overdose Cohort (ODC) was created following the declaration of the public health emergency in British Columbia (BC), Canada. The ODC is a set of longitudinal and linked administrative data which identifies illicit drug-related overdose events, including death, ambulance, emergency room, hospital, physician, and prescription drug records. Objectives and ApproachThe ODC was developed to better understand factors associated with overdose in order to support response activities, prevent overdose deaths, and identify trends and opportunities for interventions. Person-level linkages were conducted using provincial health insurance and health history data; socio-economic information, mental and physical illness diagnoses, and corrections history were also appended. The ODC currently includes people who have had a drug-related overdose between January 1 st 2015 and December 31 st 2017 as well as a 20% random sample of the general population. ResultsThe ODC contains 36,576 overdose episodes and 23,161 people who have a drug-related overdose between January 1 st , 2015 and December 31 st 2017. Of the 23,161 people, 3,604 (15.6%) had a fatal overdose and 19,557 (84.4%) had a non-fatal overdose. 49.9% of people in BC who had an overdose were 20-39 years of age and 67.4% were males. From 2015 to 2017, the proportion of people experiencing 3 or more overdoses a year increased from 3.6% to 8.7%, respectively. There were an increasing number of fatal and non-fatal drug-related overdoses in BC during this time period. Conclusion / ImplicationsLarge population data linkages can be invaluable tools during a public health emergency. Collaborative partnerships and a shared data governance across jurisdictions was central in building the ODC and understanding how various social determinants of health impact risk of overdose among people who use drugs.

Snowfall, Temperature, and the Risk of Death From Myocardial Infarction: A Case-Crossover Study

Previous research has associated snowfall with risk of myocardial infarction (MI). Most studies have been conducted in regions with harsh winters; it remains unclear whether snowfall is associated with risk of MI in regions with milder or more varied climates. A case-crossover design was used to investigate the association between snowfall and death from MI in British Columbia, Canada. Deaths from MI among British Columbia residents between October 15 and March 31 from 2009 to 2017 were identified. The day of each death from MI was treated as the case day, and each case day was matched to control days drawn from the same day of the week during the same month. Daily snowfall amount was assigned to case and control days at the residential address, using weather stations within 15 km of the residence and 100 m in elevation. In total, 3,300 MI case days were matched to 10,441 control days. Compared with days that had no snowfall, odds of death from MI increased 34% (95% confidence interval: 0%, 80%) on days with heavy snowfall (≥5 cm). In stratified analysis of deaths from MI as a function of both maximum temperature and snowfall, risk was significantly increased on snowfall days when the temperature was warmer.

Overdose and risk factors for coronavirus disease 2019

BACKGROUND

There have been significant efforts to respond to the two public health emergencies of coronavirus disease 2019 (COVID-19) and overdose in British Columbia (BC), Canada. The purpose of this study was to quantify the prevalence of known risk factors associated with mortality due to COVID-19 for persons who have had a non-fatal overdose during 2015-2017 in comparison to persons who have not had an overdose.

METHODS

Data were extracted from the BC Provincial Overdose Cohort which includes a 20 % random sample of BC residents and persons who have had a non-fatal overdose in BC from January 2015 to December 2017. Chi-square tests and logistic regression were used to compare risk factors by overdose history.

RESULTS

Persons who had a non-fatal overdose were significantly more likely to have three (chronic pulmonary disease, diabetes, coronary heart disease) of the four known chronic conditions associated with the development of severe illness due to COVID-19 compared to persons who did not have a previous non-fatal overdose event.

CONCLUSION

Persons who had an overdose were more likely to have several chronic conditions associated with the development of severe illness due to COVID-19. The increased likelihood of having these risk factors is reflective of the social and health inequities experienced by persons who have a history of overdose.

Different types of housing and respiratory health outcomes

Evidence has shown that housing conditions may substantially influence the health of residents. Different types of housing have different structures and construction materials, which may affect indoor environment and housing conditions. This study aimed to investigate whether people living in different types of housing have different respiratory health outcomes. The data from the 1999-2006 National Health and Nutrition Examination Survey were used for the analyses. The types of housing included houses, townhouses, apartments, and mobile homes. Respiratory symptoms included wheezing, coughing, sputum, and dyspnea; respiratory diseases included asthma, chronic bronchitis, emphysema, and chronic obstructive pulmonary disease (COPD). Multiple logistic regression was used to calculate odds ratio (OR) and 95% confidence interval (CI) after adjustment for potential confounding factors. A total of 11,785 participants aged 40 years and older were included in the analyses. Compared with those living in single family houses, participants living in mobile homes were more likely to have respiratory conditions, the OR (95% CI) was 1.38 (1.13-1.69) for wheezing, and 1.49 (1.25-1.78) for dyspnea; whereas participants living in apartments were less likely to have respiratory conditions, the OR (95% CI) was 0.58 (0.36-0.91) for chronic bronchitis, and 0.69 (0.49-0.97) for COPD. Compared with living in single family houses, living in mobile home was associated with worse, whereas living in apartments was associated with better, respiratory health outcomes. Further research is needed to better understand the underlying mechanisms and prevent adverse respiratory effects associated with living in mobile homes.

Exposure to loud noise, bilateral high-frequency hearing loss and coronary heart disease

OBJECTIVES

Bilateral high-frequency hearing loss is an indicator for chronic exposure to loud noise. This study aimed to examine the association between bilateral high-frequency hearing loss and the presence of coronary heart disease (CHD).

METHODS

This study included 5223 participants aged 20-69 years who participated in the audiometry examination of the National Health and Nutrition Examination Survey 1999-2004. Bilateral high-frequency hearing loss was defined as the average high-frequency (3, 4 and 6 kHz) hearing threshold ≥25 dB in both ears. CHD was defined as self-reported diagnoses by doctors or other health professionals.

RESULTS

Compared with those with normal high-frequency hearing, participants with bilateral high-frequency hearing loss were more likely to have CHD (OR 1.91; 95% CI 1.28 to 2.85) after adjustment for various covariates. This association was particularly strong for currently employed workers who were exposed to loud occupational noise (OR 4.23; 95% CI 1.32 to 13.55). For this subgroup, there was no significant association of CHD with unilateral high-frequency hearing loss, and unilateral or bilateral low-frequency hearing loss. Furthermore, there was no significant association of CHD with any types of hearing loss for participants who were not exposed to loud noise. Stratified analyses for participants exposed to loud noise showed that the observed association was particularly strong for those who were less than 50 years of age, less educated and current smokers.

CONCLUSIONS

On the basis of an objective indicator for personal chronic exposure to loud noise, this study confirmed that exposure to loud occupational noise is associated with the presence of CHD.

Long-term exposure to traffic-related air pollution and progression of carotid artery atherosclerosis: a prospective cohort study

OBJECTIVES

Epidemiological studies have demonstrated associations between long-term exposure to traffic-related air pollution and coronary heart disease (CHD). Atherosclerosis is the principal pathological process responsible for CHD events, but effects of traffic-related air pollution on progression of atherosclerosis are not clear. This study aimed to investigate associations between long-term exposure to traffic-related air pollution and progression of carotid artery atherosclerosis.

SETTING

Healthy volunteers in metropolitan Vancouver, Canada.

PARTICIPANTS AND OUTCOME MEASURES

509 participants aged 30-65 years were recruited and followed for approximately 5 years. At baseline and end of follow-up, participants underwent carotid artery ultrasound examinations to assess atherosclerosis severity, including carotid intima-media thickness, plaque area, plaque number and total area. Annual change of each atherosclerosis marker during the follow-up period was calculated as the difference between these two measurements divided by years of follow-up. Living close to major roads was defined as ≤150 m from a highway or ≤50 m from a major road. Residential exposures to traffic-related air pollutants including black carbon, fine particles, nitrogen dioxide and nitric oxide were estimated using high-resolution land-use regression models. The data were analysed using general linear models adjusting for various covariates.

RESULTS

At baseline, there were no significant differences in any atherosclerosis markers between participants living close to and those living away from major roads. After follow-up, the differences in annual changes of these markers between these two groups were small and not statistically significant. Also, no significant associations were observed with concentrations of traffic-related air pollutants including black carbon, fine particles, nitrogen dioxide and nitric oxide.

CONCLUSIONS

This study did not find significant associations between traffic-related air pollution and progression of carotid artery atherosclerosis in a region with lower levels and smaller contrasts of ambient air pollution.

Associations of ambient air pollution with chronic obstructive pulmonary disease hospitalization and mortality

RATIONALE

Ambient air pollution has been suggested as a risk factor for chronic obstructive pulmonary disease (COPD). However, there is a lack of longitudinal studies to support this assertion.

OBJECTIVES

To investigate the associations of long-term exposure to elevated traffic-related air pollution and woodsmoke pollution with the risk of COPD hospitalization and mortality.

METHODS

This population-based cohort study included a 5-year exposure period and a 4-year follow-up period. All residents aged 45-85 years who resided in Metropolitan Vancouver, Canada, during the exposure period and did not have known COPD at baseline were included in this study (n = 467,994). Residential exposures to traffic-related air pollutants (black carbon, particulate matter <2.5 μm in aerodynamic diameter, nitrogen dioxide, and nitric oxide) and woodsmoke were estimated using land-use regression models and integrating changes in residences during the exposure period. COPD hospitalizations and deaths during the follow-up period were identified from provincial hospitalization and death registration databases.

MEASUREMENTS AND MAIN RESULTS

An interquartile range elevation in black carbon concentrations (0.97 × 10(-5)/m, equivalent to 0.78 μg/m(3) elemental carbon) was associated with a 6% (95% confidence interval, 2-10%) increase in COPD hospitalizations and a 7% (0-13%) increase in COPD mortality after adjustment for covariates. Exposure to higher levels of woodsmoke pollution (tertile 3 vs. tertile 1) was associated with a 15% (2-29%) increase in COPD hospitalizations. There were positive exposure-response trends for these observed associations.

CONCLUSIONS

Ambient air pollution, including traffic-related fine particulate pollution and woodsmoke pollution, is associated with an increased risk of COPD.

Modeling population exposure to community noise and air pollution in a large metropolitan area

Epidemiologic studies have shown that both air pollution and community noise are associated with cardiovascular disease mortality. Because road traffic is a major contributor to these environmental pollutants in metropolitan areas, it is plausible that the observed associations may be confounded by coexistent pollutants. As part of a large population-based cohort study to address this concern, we used a noise prediction model to assess annual average community noise levels from transportation sources in metropolitan Vancouver, Canada. The modeled annual average noise level was 64 (inter quartile range 60-68) dB(A) for the region. This model was evaluated by comparing modeled annual daytime A-weighted equivalent continuous noise levels (L(day)) with measured 5-min daytime A-weighted equivalent continuous noise levels (L(eq,day,5 min)) at 103 selected roadside sites in the study region. On average, L(day) was 6.2 (95% CI, 6.0-7.9) dB(A) higher than, but highly correlated (r=0.62; 95% CI, 0.48-0.72) with, L(eq,day,5 min). These results suggest that our model-based noise exposure assessment could approximately reflect actual noise exposure in the study region. Overall, modeled noise levels were not strongly correlated with land use regression estimates of traffic-related air pollutants including black carbon, particulate matter with aerodynamic diameter ≤2.5 μm (PM(2.5)), NO(2) and NO; the highest correlation was with black carbon (r=0.48), whereas the lowest correlation was with PM(2.5) (r=0.18). There was no consistent effect of traffic proximity on the correlations between community noise levels and traffic-related air pollutant concentrations. These results, consistent with previous studies, suggest that it is possible to assess potential adverse cardiovascular effects from long-term exposures to community noise and traffic-related air pollution in prospective epidemiologic studies.

Association of long-term exposure to community noise and traffic-related air pollution with coronary heart disease mortality

In metropolitan areas, road traffic is a major contributor to ambient air pollution and the dominant source of community noise. The authors investigated the independent and joint influences of community noise and traffic-related air pollution on risk of coronary heart disease (CHD) mortality in a population-based cohort study with a 5-year exposure period (January 1994-December 1998) and a 4-year follow-up period (January 1999-December 2002). Individuals who were 45-85 years of age and resided in metropolitan Vancouver, Canada, during the exposure period and did not have known CHD at baseline were included (n = 445,868). Individual exposures to community noise and traffic-related air pollutants, including black carbon, particulate matter less than or equal to 2.5 μm in aerodynamic diameter, nitrogen dioxide, and nitric oxide, were estimated at each person's residence using a noise prediction model and land-use regression models, respectively. CHD deaths were identified from the provincial death registration database. After adjustment for potential confounders, including traffic-related air pollutants or noise, elevations in noise and black carbon equal to the interquartile ranges were associated with 6% (95% confidence interval: 1, 11) and 4% (95% confidence interval: 1, 8) increases, respectively, in CHD mortality. Subjects in the highest noise decile had a 22% (95% confidence interval: 4, 43) increase in CHD mortality compared with persons in the lowest decile. These findings suggest that there are independent effects of traffic-related noise and air pollution on CHD mortality.

Long-term exposure to traffic-related air pollution and the risk of coronary heart disease hospitalization and mortality

BACKGROUND

Epidemiologic studies have demonstrated that exposure to road traffic is associated with adverse cardiovascular outcomes.

OBJECTIVES

We aimed to identify specific traffic-related air pollutants that are associated with the risk of coronary heart disease (CHD) morbidity and mortality to support evidence-based environmental policy making.

METHODS

This population-based cohort study included a 5-year exposure period and a 4-year follow-up period. All residents 45-85 years of age who resided in Metropolitan Vancouver during the exposure period and without known CHD at baseline were included in this study (n=452,735). Individual exposures to traffic-related air pollutants including black carbon, fine particles [aerodynamic diameter ≤ 2.5 µm (PM(2.5))], nitrogen dioxide (NO(2)), and nitric oxide were estimated at residences of the subjects using land-use regression models and integrating changes in residences during the exposure period. CHD hospitalizations and deaths during the follow-up period were identified from provincial hospitalization and death registration records.

RESULTS

An interquartile range elevation in the average concentration of black carbon (0.94 × 10(-5)/m filter absorbance, equivalent to approximately 0.8 µg/m(3) elemental carbon) was associated with a 3% increase in CHD hospitalization (95% confidence interval, 1-5%) and a 6% increase in CHD mortality (3-9%) after adjusting for age, sex, preexisting comorbidity, neighborhood socioeconomic status, and copollutants (PM(2.5) and NO(2)). There were clear linear exposure-response relationships between black carbon and coronary events.

CONCLUSIONS

Long-term exposure to traffic-related fine particulate air pollution, indicated by black carbon, may partly explain the observed associations between exposure to road traffic and adverse cardiovascular outcomes.

Exposure to occupational noise and cardiovascular disease in the United States: the National Health and Nutrition Examination Survey 1999-2004

BACKGROUND

Chronic exposure to occupational noise may be associated with increased risk of coronary heart disease (CHD) and hypertension. However, findings are inconsistent and many previous studies are limited by small sample size and inappropriate control for potential confounders. We used a nationally representative US sample to examine associations of self-reported exposure to occupational noise with CHD and hypertension.

METHODS

This cross-sectional study included 6307 participants of the National Health and Nutrition Examination Survey 1999-2004, aged ≥ 20 years and employed at the time of interview. Noise exposure assessment was based on self-reported exposure to loud noise in the workplace.

RESULTS

Compared with never exposed participants, subjects chronically exposed to occupational noise had a 2-3-fold increased prevalence of angina pectoris, myocardial infarction, CHD and isolated diastolic hypertension. After adjustment for various covariates, the odds ratios (95% CIs) for angina pectoris, CHD and isolated diastolic hypertension were 2.91 (1.35 to 6.26), 2.04 (1.16 to 3.58) and 2.23 (1.21 to 4.12), respectively. There were clear exposure-response relationships for the observed associations. Associations of noise exposure with angina pectoris, myocardial infarction and CHD were particularly strong for participants aged < 50 years, men and current smokers. There was no significant increase in levels of cardiovascular biomarkers including blood lipids and circulating inflammatory mediators associated with noise exposure.

CONCLUSIONS

Chronic exposure to occupational noise is strongly associated with prevalence of CHD, especially for young male current smokers. This study suggests that excess noise exposure in the workplace is an important occupational health issue and deserves special attention.

Sex-related differences in serum cotinine concentrations in daily cigarette smokers

Self-reported use of cigarettes generally underestimates the true cigarette exposure of smokers. Serum cotinine is considered the best biomarker to evaluate tobacco exposure. This study determined whether or not there were any significant differences in serum cotinine concentrations between men and women when they reported smoking the same number of cigarettes per day. We analyzed cotinine and tobacco consumption data on 680 women and 840 men, aged 20 years or older, who smoked at least 100 cigarettes during their lifetime and were still actively smoking at the time of the National Health and Nutrition Examination Surveys (1999-2002). Overall, compared with men, women reported smoking fewer cigarettes per day (16.1 vs. 18.7, p<.001) and had lower serum cotinine concentrations (1163.3 nmol/L vs. 1343.9 nmol/L, p<.001). Women were more likely than men to smoke filtered (p = .018) and mentholated (p<.001) cigarettes. After adjustment for the number of cigarettes smoked per day, age, race, body mass index, poverty status, the use of either menthol or regular cigarettes, and the nicotine content in cigarettes, female compared with male smokers had lower serum cotinine concentrations (difference of 117.6 nmol/L; 95% CI = 42.6-192.6, p = .003). The difference was particularly notable in moderate to heavy smokers (i.e., those who smoked more than 15 cigarettes/day). These findings indicate that significant sex-related differences exist in serum cotinine levels among smokers, which suggests that self-reports may overestimate cigarette exposure in women compared with men.

Female smokers beyond the perimenopausal period are at increased risk of chronic obstructive pulmonary disease: a systematic review and meta-analysis

BACKGROUND

Recent reports indicate that over the next decade rates of chronic obstructive pulmonary disease (COPD) in women will exceed those in men in the western world, though in most jurisdictions, women continue to smoke less compared with men. Whether female adult smokers are biologically more susceptible to COPD is unknown. This study reviewed the available evidence to determine whether female adult smokers have a faster decline in forced expiratory volume in one second (FEV1) compared with male adult smokers and whether age modifies the relationship between cigarette smoke and lung function decline.

METHODS

A systematic review and a meta-analysis was performed of population-based cohort studies that had a follow-up period of at least 3 years, measured FEV1 on at least two different time points, and presented FEV1 data stratified by gender and smoking status in adults.

RESULTS

Of the 646 potentially relevant articles, 11 studies met these criteria and were included in the analyses (N = 55,709 participants). There was heterogeneity in gender-related results across the studies. However, on average current smokers had a faster annual decline rate in FEV1% predicted compared with never and former smokers. Female current smokers had with increasing age a significantly faster annual decline in FEV1% predicted than male current smokers (linear regression analysis, R2 = 0.56; p = 0.008). Age did not materially affect the rate of decline in FEV1% predicted in male and female former and never smokers (p = 0.775 and p = 0.326, respectively).

CONCLUSION

As female smokers age, they appear to experience an accelerated decline in FEV1% predicted compared with male smokers. Future research powered specifically on gender-related changes in lung function is needed to confirm these early findings.

Relationship between reduced forced expiratory volume in one second and the risk of lung cancer: a systematic review and meta-analysis

BACKGROUND

Individuals with severely impaired lung function have an increased risk of lung cancer. Whether milder reductions in forced expiratory volume in 1 second (FEV(1)) also increase the risk of lung cancer is controversial. Moreover, there is little consensus on whether men and women have similar risks for lung cancer for similar decreases in FEV(1).

METHODS

A search was conducted of PubMed and EMBASE from January 1966 to January 2005 and studies that examined the relationship between FEV1 and lung cancer were identified. The search was limited to studies that were population based, employed a prospective design, were large in size (> or = 5000 participants), and adjusted for cigarette smoking status.

RESULTS

Twenty eight abstracts were identified, six of which did not report FEV1 and eight did not adjust for smoking. Included in this report are four studies that reported FEV1 in quintiles. The risk of lung cancer increased with decreasing FEV1. Compared with the highest quintile of FEV1 (> 100% of predicted), the lowest quintile of FEV1 (< approximately 70% of predicted) was associated with a 2.23 fold (95% confidence interval (CI) 1.73 to 2.86) increase in the risk for lung cancer in men and a 3.97 fold increase in women (95% CI 1.93 to 8.25). Even relatively small decrements in FEV1 ( approximately 90% of predicted) increased the risk for lung cancer by 30% in men (95% CI 1.05 to 1.62) and 2.64 fold in women (95% CI 1.30 to 5.31).

CONCLUSION

Reduced FEV1 is strongly associated with lung cancer. Even a relatively modest reduction in FEV1 is a significant predictor of lung cancer, especially among women.

The Interactions Between Cigarette Smoking and Reduced Lung Function on Systemic Inflammation

BACKGROUND

Low-grade systemic inflammation is commonly observed in conditions associated with reduced FEV(1). Active cigarette smoking, which is a leading risk factor for decreased FEV(1), can also independently induce systemic inflammation.

STUDY OBJECTIVES

To determine the independent contributions of active cigarette smoking and reduced FEV(1) (as well as their potential interactions) on systemic inflammation.

DESIGN

Cross-sectional survey.

SETTING

The US general population.

PARTICIPANTS

A total of 7,685 adult participants, >/= 40 years of age, in the Third National Health and Nutrition Examination Survey, who had acceptable data on spirometry and laboratory measurements such as serum C-reactive protein (CRP).

MEASUREMENTS

The participants were stratified into four equal groups (quartiles) based on the percent predicted FEV(1) values. Each group was further categorized as active smokers or nonsmokers according to serum cotinine level (ie, >/= 10 or < 10 ng/mL). Serum levels of CRP, plasma fibrinogen, blood leukocytes, and platelets were compared across the predicted FEV(1) quartile groups and across smoking status using multiple logistic regression models.

RESULTS

We found that active smoking by itself increased the odds of having elevated CRP levels by 63% (adjusted odds ratio [OR], 1.63; 95% confidence interval, 1.28 to 2.09). The adjusted OR for reduced FEV(1) was 2.27 (95% confidence interval, 1.92 to 2.70). Having both risk factors increased the OR to 3.31 (95% confidence interval, 2.73 to 4.02). Similar findings were observed for blood leukocytes and plasma fibrinogen.

CONCLUSION

These findings suggest an additive effect of active smoking and reduced FEV(1) on markers of systemic inflammation and suggest their potential interactions in the pathogenesis of systemic complications observed in patients with poor lung function.

Combination Therapy of Inhaled Corticosteroids and Long-Acting β2- Adrenergics In Management of Patients with Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) affects over 5% of the adult population and is the only major cause of death in the United States where morbidity and mortality are increasing. Clinically, COPD is characterized by irreversible airflow obstruction and airway inflammation that eventually lead to dyspnea, cough and sputum production. Long-acting beta(2)-agonists (LABAs) are effective in reducing patient symptoms through their bronchodilatory action on airway smooth muscle. More importantly, when LABAs are given in conjunction with inhaled corticosteroids, they appear to provide added benefits for patients. While the mechanisms for this observation are not entirely clear, there is emerging evidence to indicate that LABAs and corticosteroids attenuate different but complementary components of the inflammatory cascade related to COPD. Moreover, LABAs and corticosteroids may beneficially interact to prevent downregulation of beta(2)-receptors in airway cells (and thereby preventing tachyphylaxis) and to facilitate translocation of glucocorticoid receptors into the nucleus of inflammatory cells (thereby, amplifying the anti-inflammatory activity of the corticosteroid). Regardless of the mechanism, several large, high-quality randomized controlled clinical trials indicate that combination therapy of LABA with inhaled corticosteroids improves patient symptoms, and reduces exacerbations by a third (compared to placebo). More importantly, combination therapy produces superior health outcomes than mono-therapy with inhaled corticosteroids or LABA, suggesting added clinical benefits of these two compounds in COPD. This article will present a comprehensive overview of the currently available clinical evidence for the use of combination therapy as well as the potential mechanisms of their actions in COPD.

Association between chronic obstructive pulmonary disease and systemic inflammation: a systematic review and a meta-analysis

BACKGROUND

Individuals with chronic obstructive pulmonary disease (COPD) are at increased risk of cardiovascular diseases, osteoporosis, and muscle wasting. Systemic inflammation may be involved in the pathogenesis of these disorders. A study was undertaken to determine whether systemic inflammation is present in stable COPD.

METHODS

A systematic review was conducted of studies which reported on the relationship between COPD, forced expiratory volume in 1 second (FEV(1)) or forced vital capacity (FVC), and levels of various systemic inflammatory markers: C-reactive protein (CRP), fibrinogen, leucocytes, tumour necrosis factor-alpha (TNF-alpha), and interleukins 6 and 8. Where possible the results were pooled together to produce a summary estimate using a random or fixed effects model.

RESULTS

Fourteen original studies were identified. Overall, the standardised mean difference in the CRP level between COPD and control subjects was 0.53 units (95% confidence interval (CI) 0.34 to 0.72). The standardised mean difference in the fibrinogen level was 0.47 units (95% CI 0.29 to 0.65). Circulating leucocytes were also higher in COPD than in control subjects (standardised mean difference 0.44 units (95% CI 0.20 to 0.67)), as were serum TNF-alpha levels (standardised mean difference 0.59 units (95% CI 0.29 to 0.89)).

CONCLUSIONS

Reduced lung function is associated with increased levels of systemic inflammatory markers which may have important pathophysiological and therapeutic implications for subjects with stable COPD.

Pharmacological management to reduce exacerbations in adults with asthma: a systematic review and meta-analysis

CONTEXT

Over the last 2 decades, many new pharmacological agents have been introduced to reduce the growing morbidity associated with asthma, but the long-term effects of these agents on exacerbations are unclear.

OBJECTIVE

To systematically review and quantitatively synthesize the long-term effects of inhaled corticosteroids, long-acting beta2 agonists, leukotriene pathway modifiers/receptor antagonists, and anti-IgE therapies on clinical outcomes and particular clinically relevant exacerbations in adult patients with chronic asthma.

DATA SOURCES

MEDLINE, EMBASE, and Cochrane databases were searched to identify relevant randomized controlled trials and systematic reviews published from January 1, 1980, to April 30, 2004. We identified additional studies by searching bibliographies of retrieved articles and contacting experts in the field.

STUDY SELECTION AND DATA EXTRACTION

Included trials were double-blind, had follow-up periods of at least 3 months, and contained data on exacerbations and/or forced expiratory volume in 1 second. The effects of interventions were compared with placebo, short-acting beta2 agonists, or each other.

DATA SYNTHESIS

Inhaled corticosteroids were most effective, reducing exacerbations by nearly 55% compared with placebo or short-acting beta2 agonists (relative risk [RR], 0.46; 95% confidence interval [CI], 0.34-0.62; P<.001 for heterogeneity). Compared with placebo, the use of long-acting beta2 agonists was associated with 25% fewer exacerbations (RR, 0.75; 95% CI, 0.64-0.88; P =.43 for heterogeneity); when added to inhaled corticosteroids, there was a 26% reduction above that achieved by steroid monotherapy (RR, 0.74; 95% CI, 0.61-0.91; P =.07 for heterogeneity). Combination therapy was associated with fewer exacerbations than was increasing the dose of inhaled corticosteroids (RR, 0.86; 95% CI, 0.76-0.96; P =.65 for heterogeneity). Compared with placebo, leukotriene modifiers/receptor antagonists reduced exacerbations by 41% (RR, 0.59; 95% CI, 0.49-0.71; P =.44 for heterogeneity) but were less effective than inhaled corticosteroids (RR, 1.72; 95% CI, 1.28-2.31; P =.91 for heterogeneity). Use of monoclonal anti-IgE antibodies with concomitant inhaled corticosteroid therapy was associated with 45% fewer exacerbations (RR, 0.55; 95% CI, 0.45-0.66; P =.15 for heterogeneity).

CONCLUSIONS

Inhaled corticosteroids are the single most effective therapy for adult patients with asthma. However, for those unable or unwilling to take corticosteroids, the use of leukotriene modifiers/receptor agonists appears reasonable. Long-acting beta2 agonists may be added to corticosteroids for those who remain symptomatic despite low-dose steroid therapy. Anti-IgE therapy may be considered as adjunctive therapy for young adults with asthma who have clear evidence of allergies and elevated serum IgE levels.

[The effect of Beijing Fangshan Cardiovascular Prevention Program on the incidence and mortality of stroke]

OBJECTIVE

To explore potential effective measures for lowering incidence and mortality of stroke in rural community population of China.

METHODS

Beijing Fangshan Cardiovascular Prevention Program (BFCP), under whole population and high risk individuals strategies with measures of health education and hypertension control, were launched in 1991 in five communities including intervention communities (IC), about 66,000 residents, and control communities (CC), about 54,000 residents, in Fangshan, Beijing suburb.

RESULT

Incidences of stroke averaged 235.23 per 100,000 and 289.22 per 100,000, for IC and CC respectively, with a statistically significant difference, and mortalities of stroke averaged 80.63 per 100,000 and 98.01 per 100,000, for IC and CC respectively, with a statistically significant difference, during years of 1992 to 1999. The net change of stroke incidence was 126.13 per 100,000 in IC versus CC, with a statistically significant difference. Incidences of stroke increased by 11.63% and 75.27%, for IC and CC respectively, while mortalities of stroke decreased by 46.80% and 22.82%, respectively, for IC and CC from years of 1992 to 1999.

CONCLUSION

BFCP has yielded obvious effect on controlling incidence and mortality of stroke in rural community population, but the trend of stroke incidence increasing was still not restrained radically.

[Effects of 8 years community intervention on risk factors of cardiovascular diseases in Fangshan Beijing]

OBJECTIVE

To study the changes of risk factors of cardiovascular disease in the rural community population after intervention.

METHODS

The Beijing Fangshan cardiovascular prevention program was a community-based comprehensive intervention study which was launched from 1991 and ended in 2000 in five communities including three as intervention communities (IC) and two as control communities (CC) in Fangshan, Beijing suburb. The intervention measures were focused on health education and hypertension control. The changes of risk factors of cardiovascular disease in IC and CC were analyzed using random sample in the year 1991, 1995 and 1999, respectively. The risk factors include systolic and diastolic blood pressure (SBP and DBP), body mass index(BMI), serum total cholesterol(TC), triglyceride(TG), high-density lipoprotein cholesterol(HDL), smoking, and drinking.

RESULTS

From the year 1991 to 1999, the risk factors of cardiovascular disease such as SBP, DBP, smoking rate and drinking rate were reduced in the population of IC. For male in IC, the decline of SBP, DBP, smoking rate, and drinking rate were 1.6 mmHg, 1.1 mmHg, 14.5% (P < 0.01) and 3.7%, respectively. For female of IC, SBP and DBP declined 4.8 mmHg (P < 0.01) and 3.2 mmHg (P < 0.01), respectively. SBP, DBP and smoking rate in the population of CC had a little reduction while BMI, TC and TG increased in both IC and CC. During the period of 1991 to 1999, most cardiovascular risk factors in the population of IC had net reduction compared to that of CC.

CONCLUSIONS

Except for BMI and lipids, rural community intervention, as focused on health education and hypertension control, has resulted in the reduction of most risk factors of cardiovascular disease.