Adverse lifestyle leads to an annual excess of 2 million deaths in China.

BACKGROUND: Adverse lifestyle factors have been associated with increased mortality, but data are lacking on their combined effect in developing populations, which we address in the present study. METHODS: In a death registry-based, case-control study among Hong Kong Chinese aged 30+y, proxy-reported lifestyle factors 10 y ago were collected for 21,363 cases (81% of all deaths) and 12,048 living controls. Risks associated with poor diet, inactivity, heavy alcohol intake, and smoking for all-cause and cause-specific mortality, adjusting for potential confounders, were determined, and excess deaths for the Chinese population were calculated. RESULTS: Adjusted odds ratios for all-cause mortality were 1.15 (95% CI 1.09, 1.23), 1.34 (1.27, 1.43), 1.36 (1.21, 1.52), and 1.58 (1.46, 1.70) for poor diet, inactivity, heavy alcohol intake and smoking, respectively. Increasing numbers of adverse lifestyle factors were associated with a dose-dependent increase in adjusted odds ratios of 1.30 (1.20, 1.40), 1.67 (1.54, 1.81), 2.32 (2.08, 2.60), and 3.85 (3.12, 4.75) for 1, 2, 3, and 4 risk factors relative to those with none. The population attributable fraction for all-cause, all-CVD and all-cancer mortality were 26.6%, 15.0%, and 32.1%, resulting in an excess of 2,017,541; 489,884; and 607,517 deaths annually, respectively. Although smoking was associated with the greatest excess loss of life (867,530), heavy drinking (680,466), and physical inactivity (678,317) were similarly important. CONCLUSION: Adverse lifestyle factors contribute to one quarter of all deaths in China. Improving lifestyle practices, particularly focussing on moderating alcohol intake and increasing activity, and smoking cessation are critical to reducing the lifestyle-associated health burden.

Association between television viewing and self-esteem in children.

OBJECTIVE: Few studies have examined the effect of excess television (TV) viewing on specific mental health outcomes, such as self-esteem. We explored the cross-sectional association between TV viewing hours and self-esteem in young children. METHODS: A total of 70,210 primary 4 (US grade 4) participants of the Department of Health Student Health Service, Hong Kong, in 1998-2000 reported TV viewing hours in a standardized questionnaire. Self-esteem was assessed using the Culture-Free Self-Esteem Inventories for Children (SEI) with 4 subscales. Multivariate linear regression yielded beta coefficients (ß) for SEI subscale scores by TV hours, adjusting for age, sex, body mass index, lifestyle characteristics, and highest parental education and occupational status. RESULTS: Only 10.9% of children watched >4 hours per day, while 45.3% watched TV for 1 to ≤2 hours per day. Compared with children who watched <1 hour of TV per day, those who watched a moderate amount (1 to ≤2 hours/day) had higher (more favorable) SEI scores in the General (ß = 0.09; 95% confidence interval = 0.02-0.16), Social (0.05; 0.01-0.09), and Parent-Related (0.04; 0.00-0.08) subscales but lower scores in the Academic subscale (-0.06; -0.09 to -0.02). Children who watched >2 hours of TV per day had lower SEI scores than those who watched <1 hour per day in all 4 subscales. CONCLUSIONS: An inverted J-shaped relation was observed between TV viewing hours and self-esteem among young children. The development of self-esteem among children who report little or excessive TV viewing should be further studied.

Lifestyle and socioeconomic correlates of breakfast skipping in Hong Kong primary 4 schoolchildren.

OBJECTIVE: Although breakfast is associated with different benefits, breakfast skipping is increasingly common among children. This study aimed to identify lifestyle and socioeconomic correlates of breakfast skipping in Hong Kong schoolchildren. METHODS: 68,606 primary 4 participants of the Department of Health Student Health Service in 1998-2000 reported breakfast habit and other lifestyle characteristics using a standardized questionnaire. Height and weight were measured by trained SHS nurses. Socioeconomic data were reported by parents. In cross-sectional analysis, multivariate logistic regression was used to identify lifestyle and socioeconomic correlates of breakfast skipping. RESULTS: 3,598 subjects (5.2%) usually skipped breakfast. Breakfast skipping was associated with being overweight (Odds ratio=1.59, 95% CI: 1.46 to 1.73) and obese (2.06, 1.80 to 2.36), and unhealthy dietary habits including more frequent junk food (1.23, 1.14 to 1.33) but less frequent fruit/vegetable (1.23, 1.13 to 1.34) and milk (1.98, 1.80 to 2.16) intake. Breakfast skippers tended to skip lunch, do less extra-curricular physical activity, watch more television and have less educated parents. CONCLUSIONS: Breakfast skipping was significantly related to various health-compromising lifestyle characteristics and lower parental education. Breakfast habit can be a potential lifestyle indicator. Education programmes aimed at specific target groups should encourage regular breakfast consumption.

Fish consumption and mortality in Hong Kong Chinese--the LIMOR study.

PURPOSE: To investigate the association between fish consumption and mortality in 36,003 Chinese. METHODS: A case-control study collected 81% of all deaths of those aged 30+ from all four Hong Kong death registries in 1998. Relatives registering the deaths provided demographic, dietary and other lifestyle data for the deceased (case) and a similarly aged living person (control). Causes of death were provided by the Department of Health. Logistic regression was used to calculate the mortality odds ratios (ORs) for fish consumption adjusting for potential confounders in the 23,608 cases and 12,395 controls. RESULTS: Compared with the lowest fish consumption of less than or equal to three times a month, higher consumption of one to three times a week was associated with lower mortality ORs (95% confidence interval [CI]) of 0.75 (0.62-0.89) for all-cause, 0.66 (0.48-0.92) for ischemic heart disease (IHD), 0.70 (0.50-0.98) for stroke, 0.66 (0.53-0.82) for cancer, but not for injury and poisoning. The highest level of fish consumption of greater than or equal to four times a week also reduced mortality with ORs (95% CI) of 0.80 (0.68-0.94) for all-cause and 0.63 (0.47-0.85) for IHD. CONCLUSIONS: Fish consumption significantly reduced mortality from several causes in this sample. Further longitudinal studies to confirm the association are needed.

A meta-analysis of the clinical effectiveness of school scoliosis screening.

STUDY DESIGN: A meta-analysis that systematically reviewed the evaluation studies of a scoliosis screening program reported in the literature. OBJECTIVE: To evaluate the best current evidence on the clinical effectiveness of school screening for adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: The use of school scoliosis screening is controversial, and its clinical effectiveness has been diversely reported. METHODS: Data sources included 3 databases, namely, PubMed, Google scholar, CINAHL database, and the references from identified reviews and studies. Studies were included if: (1) they adopted a retrospective cohort design; (2) were screened using either the forward bending test (FBT), angle of trunk rotation, or Moiré topography; (3) reported results of screening tests and radiographic assessments; (4) screened adolescents only; (5) reported the incidence of curves with a minimum Cobb angle of 10 degrees or greater; and (6) reported the number of referrals for radiography. Reviews, comments, case studies, and editorials were excluded. RESULTS: Thirty-six studies, including 34 from the 775 initially identified studies and 2 from the references, met the selection criteria. The pooled referral rate for radiography was 5.0%, and the pooled positive predictive values for detecting curves > or =10 degrees , curves > or =20 degrees , and treatment were 28.0%, 5.6%, and 2.6%, respectively. There was substantial heterogeneity across studies. Meta-regression showed that programs using the FBT alone reported a higher referral rate (odds ratio [OR] = 2.91) and lower positive predictive values for curves > or =10 degrees (OR = 0.49) and curves > or =20 degrees (OR = 0.34) than programs using other tests. Only one small study followed students until skeletal maturity and reported the sensitivity of screening; however, the specificity was not reported. No severe publication bias was noted. CONCLUSION: The use of the FBT alone in school scoliosis screening is insufficient. We need large, retrospective cohort studies with sufficient follow-up to properly assess the clinical effectiveness of school scoliosis screening.

Alcohol and cardio-respiratory deaths in Chinese: a population-based case-control study of 32,462 older Hong Kong adults.

BACKGROUND: In observational studies moderate alcohol use reduces cardio-respiratory mortality. However observational studies may be biased by many factors including residual confounding by unmeasured differences between moderate alcohol users and other groups or by changes in alcohol use with ill-health and aging. We used two different analytic strategies in an under-studied population, i.e. southern Chinese, to provide an assessment of the specific impact of moderate alcohol use on mortality from ischemic heart disease (IHD) and chronic obstructive pulmonary diseases (COPD). METHODS: In a population-based case-control study of all adult deaths in Hong Kong Chinese in 1998, we used adjusted logistic regression to compare alcohol use in decedents aged > or = 60 years from IHD (2270) and COPD (1441) with 10,320 living and 9043 dead controls (all non-alcohol related deaths). We also examined whether the association of alcohol use with death from IHD or COPD varied with sex or smoking status. RESULTS: Using living controls and adjusted for age, socio-economic status and lifestyle, occasional and moderate alcohol use were generally associated with lower mortality from IHD and COPD. However, using dead controls the protection of occasional and moderate alcohol use appeared to be limited to ever-smokers for IHD (odds ratio (OR) 0.58, 95% confidence interval (CI) 0.46 to 0.73 for moderate compared to never-use in ever-smokers, but OR 1.07, 95% CI 0.76 to 1.50 in never-smokers), and possibly to men for COPD. High alcohol use was associated with lower IHD mortality and possibly with lower COPD mortality. CONCLUSION: High levels of alcohol use in an older Chinese population were associated with lower IHD mortality. Moderate alcohol use was less consistently protective against IHD mortality. Alcohol use was associated with lower COPD mortality particularly in men, either due to some yet to be clarified properties of alcohol or as the artefactual result of genetic selection into alcohol use in a Chinese population. Given the increasing use of alcohol in China with economic development, other designs and analytic strategies are needed to assess the impact of alcohol in this population, so that an evidence-based public health policy can be formulated.

Secular changes in height, weight and body mass index in Hong Kong Children.

BACKGROUND: Large population growth surveys of children and adolescents aged 6 to 18 y were undertaken in Hong Kong in 1963 and 1993. The global epidemic of obesity is a major public health concern. To monitor the impact of this epidemic in Hong Kong children and to identify secular changes in growth, a further growth survey was undertaken in 2005/6. METHODS: Cross-sectional height and weight measurements of 14,842 children and adolescents aged 6 to 18 y from Hong Kong's 18 districts were obtained during the 2005/6 school year. Percentile curves were constructed using LMS method and sex-specific percentile values of weight-for-age, height-for-age, and BMI-for-age were compared with those data from 1963 and 1993. RESULTS: Secular changes in height, weight and BMI were noted between 1963 and 1993 and between 1993 and 2005/6. In the latter period, greater changes were observed at younger ages, and particularly in boys. On an annual basis, the 1993-2005/6 changes were less than those during 1963-1993. Using the International Obesity Task Force cut-offs, 16.7% of children were overweight or obese in 2005/6, which was a 5.1% increase since 1993. CONCLUSION: These data provide policy-makers with further evidence of the secular changes in child growth and the increasing obesity epidemic among Hong Kong children.

Birth weight, infant growth, and childhood body mass index: Hong Kong's children of 1997 birth cohort.

OBJECTIVE: To investigate the association between birth weight, infant growth rate, and childhood adiposity as a proxy for adult metabolic or cardiovascular risk in a Chinese population with a history of recent and rapid economic development. DESIGN: Prospective study in a population-representative birth cohort. SETTING: Hong Kong Chinese population. PARTICIPANTS: Six thousand seventy-five term births (77.5% successful follow-up). Main Exposures Birth weight and growth rate (change in the weight z score) at ages 0 to 3 and 3 to 12 months. Main Outcome Measure Body mass index (BMI) (calculated as the weight in kilograms divided by the height in meters squared) z score at about age 7 years. RESULTS: Each unit increase in the weight z score at ages 0 to 3 and 3 to 12 months increased the BMI z score by 0.52 and 0.33, respectively. Children in the highest birth weight and growth rate tertiles had the highest BMI z scores. In the lowest birth weight tertile, increases in the weight z score at ages 0 to 3 months had a larger effect on the BMI z score in boys (mean difference, 0.88; 95% confidence interval 0.69-1.07) than in girls (mean difference, 0.52; 95% confidence interval, 0.33-0.71); these differences by birth weight, growth rate at ages 0 to 3 months, and sex were significant (P = .007). CONCLUSIONS: Faster prenatal and postnatal growth were associated with higher childhood BMI in a population with a recent history of rapid economic growth and relatively low birth weight, suggesting that maximal growth may not be optimal for metabolic risk. However, there may be a developmental trade-off between metabolic risk and other outcomes.

Oscillometrically measured blood pressure in Hong Kong Chinese children and associations with anthropometric parameters.

BACKGROUND: Oscillometric devices are increasingly used to measure blood pressure (BP). Reference data are limited and have not used devices validated against sphygmomanometric measurements on which current standards are based. BP standards for Chinese children have been based on sphygmomanometry and have not provided height-related or weight-related BP percentiles. METHODS: BP was measured in 14842 Hong Kong Chinese schoolchildren aged 6-18 years randomly selected from 36 schools in the 18 Hong Kong districts, using a validated oscillometric device (Datascope Accutorr Plus). Height, weight, heart rate and waist circumference were measured. Percentiles for systolic BP and diastolic BP by sex, age, height and weight were generated. Features associated with systolic BP and diastolic BP in 12680 children were analysed by univariate and multivariate analysis. RESULTS: Reference BP standards by sex, age, weight and height are presented. BP was associated (in descending order of strength) with weight > height > age > waist circumference > body mass index, and weakly with heart rate (which added considerable influence on multivariate analysis). BP increases similarly with age, height (which can normalize for variations in growth) and weight (which is associated most strongly with BP). BP was associated also with family history of high BP and (inversely) with sleep duration. CONCLUSIONS: The study provides oscillometrically measured BP standards for Chinese children, with age-related and sex-related height-specific and weight-specific percentiles. Implications of the findings are discussed. Screening by sex-specific BP-height percentile charts, and then if high, reference to the BP-sex-age-weight table, is suggested.

Does economic development contribute to sex differences in ischaemic heart disease mortality? Hong Kong as a natural experiment using a case-control study.

BACKGROUND: The male excess risk of premature ischemic heart disease (IHD) mortality may be partially due to an unknown macro-environmental influence associated with economic development. We examined whether excess male risk of IHD mortality was higher with birth in an economically developed environment. METHODS: We used multivariable logistic regression in a population-based case-control study of all adult deaths in Hong Kong Chinese in 1998 to compare sex differences in IHD mortality (1,189 deaths in men, 1,035 deaths in women and 20,842 controls) between Hong Kong residents born in economically developed Hong Kong or in contemporaneously undeveloped Guangdong province in China. RESULTS: Younger (35-64 years) native-born Hong Kong men had a higher risk of IHD death than such women (odds ratio 2.91, 95% confidence interval 1.66 to 5.13), adjusted for age, socio-economic status and lifestyle. There was no such sex difference in Hong Kong residents who had migrated from Guangdong. There were no sex differences in pneumonia deaths by birth place. CONCLUSION: Most of these people migrated as young adults; we speculate that environmentally mediated differences in pubertal maturation (when the male disadvantage in lipids and fat patterning emerges) may contribute to excess male premature IHD mortality in developed environments.

Soy consumption and mortality in Hong Kong: proxy-reported case-control study of all older adult deaths in 1998.

OBJECTIVES: This study investigates the relation between soy consumption and mortality in a population-based case-control study in Hong Kong of all adult deaths in 1998. METHODS: Multivariable logistic regression was used to assess the effect of soy on all-cause and cause-specific mortality in 21,494 deceased cases and 10,968 living controls who were ethnic Chinese aged 60 or above, using proxy reports collected from the person registering the death. Dietary habits were obtained from proxies in both cases and controls, based on a 7-item questionnaire. RESULTS: The adjusted odds ratios for all-cause mortality for soy consumption 4 or more times a week compared with less than once a month were 0.77 (95% CI: 0.62, 0.95) for men and 0.66 (0.54, 0.81) for women. Mortality from lung cancer (males P = 0.02, females P = 0.02), colorectal cancer (males P = 0.07, females P < 0.001), stomach cancer (males P = 0.04, females P = 0.03), female breast cancer (P = 0.02) and ischemic heart disease (males P < 0.001, females P = 0.002) was inversely associated with soy consumption. CONCLUSIONS: Our study suggests that maintaining traditional levels of soy consumption could be protective for some chronic diseases in China.

Diet synergies and mortality--a population-based case-control study of 32,462 Hong Kong Chinese older adults.

BACKGROUND: Food and drink are not consumed in isolation and can have complimentary effects enhancing or blocking the overall uptake of nutrients. We investigated how combinations of foods, drinks, and smoking affected mortality. Method Adjusted logistic regression was used to assess the joint effect of healthy foods, less healthy foods, smoking, and alcohol use on mortality in a case-control study of all Chinese adults aged 60 or over who died in 1998; 21,494 dead cases (81% of all registered deaths) and 10,968 live controls were included. RESULTS: There was a significant trend of increasing all-cause mortality risk with decreasing healthy food consumption (P < 0.001), and the increase in risk was significantly steeper for people with high intakes of less healthy food (P for interaction <0.001). There was a steeper risk from increasing less healthy food intake in ever-smokers and people not drinking tea regularly (P < 0.001), while the J-shaped relationship between alcohol and mortality differed in shape with level of less healthy food intake. CONCLUSION: Intake of some dietary items may modify the effect of others. An analysis framework explicitly recognizing complementary and potentially synergistic effects of food, drinks, and smoking could enhance our understanding of dietary epidemiology.

Depressive symptoms and smoking among Hong Kong Chinese adolescents.

AIMS: To examine associations among depressive symptoms, smoking, smoking trajectories and quitting smoking in Hong Kong. DESIGN: Prospective longitudinal design, with wave 1 at baseline (T1) and wave 2 (T2) 12 months later. SETTING AND PARTICIPANTS: Form 1 (equivalent to 7th grade in the United States) students, mean age = 12.7 years, n = 1894. MEASUREMENTS: Self-reported smoking status, attempts to quit and depressive symptoms. FINDINGS: At both waves, current as well as ex-smokers had higher depressive symptoms than never smokers. T1 smoking predicted T2 depressive symptoms among those with low baseline depressive symptoms. Depressive symptoms at T1 predicted smoking at T2 among non-smokers at T1. Trajectories were defined by separating participants who were never smokers at both waves ('non-smokers'), those who smoked at both waves ('persistent smokers'), those who smoked at one time but were not smoking at either wave ('past smokers), and those who had never smoked at T1 but reported smoking a year later ('new smokers'). Persistent, past and new smokers had higher depressive symptoms at both waves than non-smokers. Smokers who reported not wanting or trying to quit and those who had been unsuccessful at quitting had higher depressive symptoms at T2 than those who successfully quit. CONCLUSION: Our results suggest that depressive symptoms promote tobacco use in Asian adolescents by making it more likely that an adolescent will begin smoking and less likely that she or he will quit. These findings elucidate risk factors in Hong Kong for two important public health concerns for adolescents: smoking and depression.

Leisure time physical activity and mortality in Hong Kong: case-control study of all adult deaths in 1998.

PURPOSE: Physical activity is associated with longevity; however, whether these beneficial effects extend to Chinese populations is unclear. We examined the relationship between leisure time physical activity (LTPA) and mortality in Hong Kong. METHODS: Using a case-control study, past (10 years prior) levels of LTPA were ascertained via proxy informants for 24,079 dead cases (81% of all registered deaths) and 13,054 live controls aged #10878;35 years and were analyzed by unmatched logistic regression to determine their association with all-cause and cause-specific mortality. RESULTS: Compared with an exercise frequency of <1 episode per month, > or = 1 episode of LTPA per month was inversely associated with all-cause mortality [multivariable odds ratio (OR)=0.63, 95% confidence interval (CI), 0.59, 0.68 for males; OR=0.75, 95% CI, 0.70, 0.80 for females; adjusted for age, education, smoking status, alcohol consumption, and physical demand at work]. Each activity level above the reference level of <1 episode per month (i.e., 1 episode per month to 1-3 episodes per week, > or = 4 episodes per week) had approximately the same level of risk reduction and no dose-response gradient was observed. The inverse association was stronger for cardiovascular than cancer deaths, particularly in males and was strongest for respiratory mortality. One-fifth of all 31,349 registered deaths in those aged 35 years and over in Hong Kong in 1998 were attributable to physical inactivity. CONCLUSION: The present data confirm and extend previous findings in Caucasian populations on the association between leisure time physical activity and longevity. The population attributable risk from physical inactivity exceeds that due to tobacco smoking in this Hong Kong Chinese population. We predict mainland China will witness a similarly large mortality burden as it undergoes further socioeconomic development in the next few decades.

Lack of evidence for human-to-human transmission of avian influenza A (H9N2) viruses in Hong Kong, China 1999.

In April 1999, isolation of avian influenza A (H9N2) viruses from humans was confirmed for the first time. H9N2 viruses were isolated from nasopharyngeal aspirate specimens collected from two children who were hospitalized with uncomplicated, febrile, upper respiratory tract illnesses in Hong Kong during March 1999. Novel influenza viruses have the potential to initiate global pandemics if they are sufficiently transmissible among humans. We conducted four retrospective cohort studies of persons exposed to these two H9N2 patients to assess whether human-to-human transmission of avian H9N2 viruses had occurred. No serologic evidence of H9N2 infection was found in family members or health-care workers who had close contact with the H9N2-infected children, suggesting that these H9N2 viruses were not easily transmitted from person to person.