Patterns of lung function in asymptomatic nonsmoking men and women in the People's Republic of China

Reference values for lung function screening in 10- to 81-year-old, healthy, never-smoking residents of Southeast China

No official spirometry reference values for Chinese are available.To establish new Chinese reference values and prediction equations for lung parameters in Chinese individuals of 10 to 81 years of age.Pulmonary functions were measured according to the American Thoracic Society criteria in 1457 subjects from the Zhejiang coastal province (China). The subjects were 10 to 81 years of age, nonsmokers, and without chronic or acute diseases. Multiple stepwise linear regression analysis was performed for each parameter against age, height, weight, and body mass index (BMI; kg/m) for males and females separately.Most lung function variables were nonlinear with age and showed a plateau in younger adults, with a decline after 31 to 35 years. All spirometric data of men were higher than those of women except breathing frequency and forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC). All measured lung function parameters were strongly correlated to age, height, weight, and BMI. The highest correlation being to height in both men and women except for tidal volume and expiratory reserve volume among women. Based on previous studies, Caucasians men from the USA and Switzerland had higher FVC and FEV1 than in the present study, but only slightly higher than American blacks, British, Pakistani, and Singapore; an inverse trend was observed for Malay and Indians. Similar relationships were observed for women. The relationship between height and lung function parameters was nonlinear, with the variance of lung function parameters increasing with increasing height. For each sex, the z scores differed significantly by BMI (P < .001).This study provides spirometry equations that can be used for Chinese individuals.

Peak Systolic Velocity Measurements with Transcranial Doppler Ultrasound Is a Predictor of Incident Stroke among the General Population in China

BACKGROUND AND OBJECTIVE

It is necessary to develop an effective and low-cost screening tool for identifying Chinese people at high risk of stroke. Transcranial Doppler ultrasound (TCD) is a powerful predictor of stroke in the pediatric sickle cell disease population, as demonstrated in the STOP trial. Our study was conducted to determine the prediction value of peak systolic velocities as measured by TCD on subsequent stroke risk in a prospective cohort of the general population from Beijing, China.

METHODS

In 2002, a prospective cohort study was conducted among 1392 residents from 11 villages of the Shijingshan district of Beijing, China. The cohort was scheduled for follow up with regard to incident stroke in 2005, 2007, and 2012 by a study team comprised of epidemiologists, nurses, and physicians. Univariate and multivariate Cox proportional hazard regression models were used to determine the factors associated with incident stroke.

RESULTS

Participants identified by TCD criteria as having intracranial stenosis had a 3.6-fold greater risk of incident stroke (hazard ratio (HR) 3.57, 95% confidence interval (CI) 1.86-6.83, P<0.01) than those without TCD evidence of intracranial stenosis. The association remained significant in multivariate analysis (HR 2.53, 95% CI 1.31-4.87) after adjusting for other risk factors or confounders. Older age, cigarette smoking, hypertension, and diabetes mellitus remained statistically significant as risk factors after controlling for other factors.

CONCLUSIONS

The study confirmed the screening value of TCD among the general population in urban China. Increasing the availability of TCD screening may help identify subjects as higher risk for stroke.

Genome-wide association study on progression of carotid artery intima media thickness over 10 years in a Chinese cohort

BACKGROUND

Carotid artery intima media thickness (IMT) in human is a marker of subclinical atherosclerosis with high heritability. Many genome-wide association studies (GWAS) were performed in European and American populations, yet discovery efforts have been limited in Asians.

OBJECTIVE

To identify the genetic determinants of 10-year progression of IMT using GWA approach in a Chinese cohort.

METHODS

Cardiovascular epidemiologic survey was carried out in 810 Chinese adults in 2012. 302,218 single-nucleotide polymorphisms (SNP) in whole genome were genotyped using gene chip and carotid IMT was measured. Most of these participants, had previous carotid IMT measurements in 2002 (n = 572), 2005 (n = 750), 2007 (n = 747), and 2010 (n = 671). General linear model (GLM) and multiple linear mixed-model (MLM) were used to assess the association between SNPs and carotid IMT.

RESULTS

The mean age (SD) of the sample was 61.3 (5.1) years; 33.6% were men. The adjusted GLM showed no SNP with significance association at genome-level (all p > 1 × 10(-7)). However, using MLM, after adjusting for age, sex, number of cigarettes smoked per day, systolic blood pressure, use of antihypertensive drugs in the past 2 weeks, serum cholesterol, body mass index, fasting glucose levels, use of insulin or hypoglycemic drugs, time of measuring IMT and its interaction with SNP, we identified two novel SNPs (rs36071027 in EBF1 gene on chromosome 5 and rs975809 close to PCDH15 gene on chromosome 10) that are significantly associated with carotid IMT at genome level (p < 1 × 10(-7)) and seven novel SNPs (rs2230307 in AGL gene on chromosome 1, rs12040273 in GALNT2 gene on chromosome 1, rs4536103 in NEUROG3 gene on chromosome 10, rs9855415 in LOC647323 gene on chromosome 3, rs2472647 in PCDHGA1 gene on chromosome 5, rs17433780 in GBP3 gene on chromosome 1, and rs7625806 in DLEC1 gene on chromosome 3) which are suggestive of significant association (p < 10(-5)).

CONCLUSION

The study represents the first GWAS of association between SNPs and carotid IMT in an Asian population. We identified 2 novel loci associated with carotid IMT progression over 10 years.

Baseline overall health-related quality of life predicts the 10-year incidence of cardiovascular events in a Chinese population

OBJECTIVE

To determine the relationship between baseline overall HRQOL as well as domain-specific HRQOL and incident cardiovascular (CV) events over 10 years of follow-up in a Chinese general population.

METHODS

We examined the above link using data from a prospective cohort study, conducted between 2002 and 2012 in 11 villages of Beijing. HRQOL was assessed using Chinese 35-item quality of life instrument, and CV risk factors were recorded in either 2002 or 2005. Subjects were followed through the end of the study period, or until they were censored due to an incident CV event [including myocardial infarction (MI) and stroke] or loss to follow-up.

RESULTS

A total of 1739 participants were eligible to be included in the current study [female 64.2 %, age 57.7 (8.4) years]. There were a total of 190 CV events during the follow-up (14,364 total person-years). Participants in the bottom 20 % had 85 % increase in risk of CV event [hazard ratio (HR) 1.85; 95 % CI 1.14-3.02] compared to those in top 20 % of overall HRQOL, after adjusting for sex, age, education, marital status, smoking, alcohol consumption, being physically active, hypertension, diabetes, high cholesterol, and obesity. Among the six HRQOL domains, the independence domain had the largest effect size (fully adjusted HR 2.91; 95 % CI 1.67-5.07), followed by physical domain (HR 1.66; 95 % CI 1.03-2.67). Other domains did not predict the incidence CV events in this cohort.

CONCLUSIONS

While overall lower HRQOL predicts subsequent risk of stroke and MI events, this appeared to be driven mainly by the independence domain.

Baseline health-related quality of life and 10-year all-cause mortality among 1739 Chinese adults

BACKGROUND AND PURPOSE

Health-related quality of life (HRQOL) may be associated with the longevity of patients; yet it is not clear whether this association holds in a general population, especially in low- and middle-income countries. The objective of this study was to determine whether baseline HRQOL was associated with 10-year all-cause mortality in a Chinese general population.

METHODS

A prospective cohort study was conducted from 2002 to 2012 on 1739 participants in 11 villages of Beijing. Baseline data on six domains of HRQOL, chronic diseases and cardiovascular risk factors were collected in either 2002 (n = 1290) or 2005 (n = 449). Subjects were followed through the end of the study period, or until they were censored due to death or loss to follow-up, whichever came first.

RESULTS

A multivariable Cox model estimated that Total HRQOL score (bottom 50% versus top 50%) was associated with a 44% increase in all-cause mortality (Hazard Ratio [HR] = 1.44; 95% confidence interval [CI]: 1.00-2.06), after adjusting for sex, age, education levels, occupation, marital status, smoking status, fruit intake, vegetable intake, physical exercise, hypertension, history of a stroke, myocardial infarction, chronic respiratory disease, and kidney disease. Among the six HRQOL domains, the Independence domain had the largest fully adjusted HR (HR = 1.66; 95% CI: 1.13-2.42), followed by Psychological (HR = 1.47; 95% CI: 1.03-2.09), Environmental (HR = 1.43, 95% CI: 1.003-2.03), Physical (HR = 1.38; 95% CI: 0.97-1.95), General (HR = 1.37; 95% CI: 0.97-1.94), and the Social domain (HR = 1.15; 95% CI: 0.81-1.65).

CONCLUSION

Lower HRQOL, especially the inability to live independently, was associated with a significantly increased risk of 10-year all-cause mortality. The inclusion of HRQOL measures in clinical assessment may improve diagnostic accuracy to improve clinical outcomes and better target public health promotions.

Cross-sectional and longitudinal association of cigarette smoking with carotid atherosclerosis in Chinese adults

OBJECTIVE

To assess the cross-sectional and longitudinal association of cigarette smoking with carotid atherosclerosis in middle-aged and older Chinese adults.

METHODS

The study population consisted of 1132 residents in Beijing (748 women and 384 men) aged 35 to 64 years. Information on baseline smoking characteristics, including smoking status and pack-years was collected in 1993-1994. The cohort was resurveyed in 2002 and common carotid artery intima-media thickness (CCA-IMT) and carotid plaques were measured by B-mode ultrasound.

RESULTS

The multivariable-adjusted mean CCA-IMT at resurvey was significantly associated with smoking status at both resurvey and baseline, and was 0.72 mm for consistent current smokers, 0.71 mm for former and inconsistent smokers, and 0.70 mm for consistent never smokers at both surveys, respectively (p-trend<0.01). The multivariable-adjusted odds ratio [OR, 95% confidence interval (CI)] of having carotid plaques was 1.5 (1.0-2.1) for consistent current smokers vs consistent never smokers. In addition, there was a significant dose-response relationship between baseline smoking pack-years and multivariable-adjusted mean CCA-IMT and risk of having carotid plaques at resurvey.

CONCLUSION

Smoking is associated with carotid atherosclerosis in middle-aged and older Chinese adults both cross-sectionally and longitudinally. Smoking cessation may play a significant role in prevention and control of cardiovascular diseases in China.

Age and gender specific lung function predictive equations provide similar predictions for both a twin population and a general population from age 6 through adolescence

BACKGROUND

There have been numerous studies of asthma in twins, but no study has evaluated whether lung function predictive models yield similar results between twin and general populations. We sought to evaluate this in late childhood and adolescent subjects.

METHODS

We generated cross-sectional, sex- and age-specific regression models of FEV(1), and FVC, in a community-based cohort of 3140 healthy, non-smoking Chinese twins using generalized estimating equations to adjust for correlations within twin pairs. We applied the model to a healthy non-smoking general population cohort of 2187 subjects from the same region, and compared %predicted FEV(1) and FVC values between the two populations.

RESULTS

Stratified by age and sex, the associations of height with FEV(1) or FVC varied by age group. During the adolescent growth spurt (age 13 for girls and ages 14-16 for boys), the associations of height with FEV(1) or FVC were nonlinear and greater than that seen at other ages. During adolescence, FEV(1) and FVC for a given height increased with age. The percent predicted values of FEV(1) and FVC in the twin population were similar to that of the general population.

CONCLUSIONS

Twin and general populations have similar patterns of lung function change over middle childhood and adolescence. Similar equations may be used to estimate percent predicted values. Finally, a single prediction equation cannot completely describe patterns of lung function from childhood through adolescence due to puberty related changes.

Allergy in bakers’ apprentices and factors associated to non-participation in a cohort study of allergic sensitization

OBJECTIVE

To describe the prevalence of atopy and respiratory symptoms among baker apprentices at the start of the education and factors associated with non-participation in the study.

METHODS

A total of 346 students, 22.1(0.6) years of age, mean (SD), from the food production programme of technical colleges in Denmark were invited to participate in a 3 year study. Of the students, 187 agreed to participate and filled in a physician-administered questionnaire. The presence of atopy was determined by skin prick test (SPT) and serum allergen specific IgE (SpIgE). Bronchial hyper responsiveness to methacholine (PD(20) <or= 1,440 microg) was determined.

RESULTS

Prevalence of atopy was 32%. The prevalence of symptoms from the lungs and nose was 19.8 and 25.5%, respectively. Significantly, more SPT reactions were seen in males compared to females (39 vs. 22%, P < 0.05). Sensitization towards flour was significantly more frequent if determined as SpIgE (7.3%) compared to SPT (0.5%). We found a positive association between atopy and lung symptoms OR 6.1 (2.8-13.2 SD) and nasal symptoms OR 3.7 (1.8-7.5 SD). The major reason for non-participation was fear of blood sampling (25.5%).

CONCLUSION

The prevalence of atopy in bakers' apprentices was of the same magnitude in the general Danish population. Significantly, more male bakers' apprentices had atopy. This finding has major impact on the diagnostic procedures of occupational allergy in bakery workers emphasizing the need for standardization of the clinical tests. The main reasons for non-participation were, fear of blood-sampling (57%) and the 3 years commitment to the follow-up study (39%).

Updated spirometric reference values for adult Chinese in Hong Kong and implications on clinical utilization

STUDY OBJECTIVES

The accuracy of reference values of lung function is important for assessment of severity and functional impairment of respiratory diseases. The aim of the study was to establish updated prediction formulae of spirometric parameters for Hong Kong Chinese and to compare the reference values with those derived from other studies in white and Chinese subjects.

DESIGN

Cross-sectional multicenter study.

SETTING

Lung function laboratories of eight regional hospitals in Hong Kong.

PARTICIPANTS

Subjects were recruited by random-digit dialing. One thousand one hundred seventy-six subjects who fulfilled recruitment criteria underwent spirometry.

MEASUREMENTS

Spirometry was performed according to American Thoracic Society recommendations, and the technique was standardized among the eight participating lung function laboratories.

RESULTS

Evaluable data of 1,089 (494 men and 595 women) healthy nonsmokers aged 18 to 80 years were analyzed. Age and height were found to be the major determinants of FEV1 and FVC, with a linear decline of height-adjusted values with age in both sexes. Spirometric values of this population have increased compared to Chinese populations of similar sex, age, and height two decades ago. Reference values derived from white populations were higher than our values by 5 to 19%, and the degree of overestimation varied with age, sex, and lung function parameter. We also demonstrated that the blanket application of correction factors for Asian populations may not be appropriate. In this study cohort, the distribution-free estimation of age-related centiles was more appropriate for the determination of lower limits of normal.

CONCLUSIONS

Our findings underscore the need to use reference values based on updated data derived from local populations or those matched for ethnicity and other sociodemographic characteristics.

Baseline pulmonary function and quality of life 9 years later in a middle-aged Chinese population

STUDY OBJECTIVE

This research examined the association of baseline pulmonary function with future quality of life (QOL).

METHODS

We collected baseline pulmonary function data in 1993 and 1994, and assessed QOL using the Chinese 35-Item Quality of Life Instrument in 2002 in a cohort of 1,356 participants. We used Pearson correlation analysis, multivariate analysis of variance, and multivariate linear regression analysis to assess the relationship between pulmonary function and QOL.

RESULTS

The baseline percentage of age- and height-predicted FEV1 (FEV1%) was significantly correlated with the resurvey total QOL score (r = 0.126, p < 0.001) and with QOL scores for the general (r = 0.074, p = 0.006), physical (r = 0.085, p = 0.002), independence (r = 0.178, p < 0.001), and psychological (r = 0.064, p = 0.018) domains but not with the social and environmental domains after adjusting for age and sex. These associations were weaker for the percentage of age- and height-predicted FVC. Multiple linear regression showed that the above associations were independent of baseline and resurvey smoking status. Inclusion of respiratory symptoms in the model reduced the regression coefficients from 0.82 to 0.41 for the total QOL score and from 1.43 to 0.94 for the independence domain score, for a 10% change in FEV1%. The age- and sex-adjusted mean total QOL scores were 78, 76, 76, and 69, respectively (p < 0.001), for the groups of normal, symptomatic only, impaired pulmonary function only, and both symptomatic and impaired pulmonary function. This trend was also significant for the general, physical, independence, and psychological domain scores.

CONCLUSION

Impaired baseline pulmonary function has a significant negative impact on QOL in later life that is independent of age, sex, height, and smoking status and is largely mediated through the development of chronic respiratory symptoms.