Next steps towards universal health coverage call for global leadership

Gerald Bloom and colleagues argue that the G20 is uniquely placed to facilitate crucial actions to accelerate progress towards universal health coverage

Influenza Hemagglutination-inhibition Antibody Titer as a Mediator of Vaccine-induced Protection for Influenza B

BACKGROUND

The hemagglutination inhibition (HAI) assay is an established correlate of protection for the inactivated influenza vaccine. However, the proportion of vaccine-induced protection that is mediated by the post-vaccination HAI titer has not been assessed.

METHODS

We used data from a randomized, placebo-controlled trial of a split-virion inactivated influenza vaccine in children aged 6-17 years. Sera were collected before and 30 days after receipt of vaccination or placebo and tested by the HAI assay against B/Brisbane/60/2008-like (B/Victoria lineage). We fitted Cox proportional hazards models to the time to laboratory-confirmed influenza B. We used causal mediation analysis to estimate the proportion of the total effect of vaccination that was mediated by higher HAI titers.

RESULTS

We estimated that vaccine efficacy against confirmed B/Victoria infection was 68% (95% confidence interval, 33%, 88%), and post-vaccination HAI titers explained 57% of the effect of vaccination on protection.

CONCLUSIONS

The majority of the effect of inactivated influenza vaccination in children is mediated by the increased HAI titer after vaccination; however, other components of the immune response to vaccination may also play a role in protection and should be further explored. Causal mediation analysis provides a framework to quantify the role of various mediators of protection.

Breastfeeding in Infancy and Lipid Profile in Adolescence

OBJECTIVES

Breast milk has higher cholesterol than formula. Infants who are breastfed have different cholesterol synthesis and metabolism in infancy than infants who are formula fed. Little is known as to whether breastfeeding is associated with subsequent lipid profile, independent of adiposity. We assessed the association of breastfeeding in early infancy with lipid profile and adiposity at ∼17.5 years in a setting where exclusive breastfeeding is not associated with higher socioeconomic position.

METHODS

We used multivariable linear regression with multiple imputation and inverse probability weighting to examine the associations of contemporaneously reported feeding in the first 3 months of life (exclusive breastfeeding [7.5%], mixed feeding [40%], or always formula feeding [52%]) with lipids and adiposity at ∼17.5 years in 3261 participants in the Hong Kong Chinese birth cohort Children of 1997, adjusting for sex, birth weight, gestational weeks, parity, pregnancy characteristics, parents' highest education, mother's place of birth, and age at follow-up.

RESULTS

Exclusive breastfeeding, but not mixed feeding at 0 to 3 months, compared with formula feeding was associated with lower total cholesterol and low-density lipoprotein cholesterol but not with high-density lipoprotein cholesterol at ∼17.5 years. BMI and fat percentage measured by bioimpedance did not differ by type of infant feeding.

CONCLUSIONS

Exclusive breastfeeding in early infancy may promote a healthier lipid profile in late adolescence through mechanisms unrelated to adiposity, implicating its potential long-term benefits for cardiovascular health.

The association of early-life exposure to air pollution with lung function at ~17.5 years in the "Children of 1997" Hong Kong Chinese Birth Cohort

BACKGROUND

Early-life air pollution exposure is associated with lung function in children and adolescents. However, whether the association of prenatal and early postnatal exposure to air pollution with lung function continues into adulthood remains unclear.

OBJECTIVE

To investigate the associations of early exposure to air pollution with lung function at ~17.5 years in a non-western developed setting with more concentrated air pollutants.

METHODS

We examined the associations of exposure to particular matter with an aerodynamic diameter of <10 μm (PM₁₀), nitrogen dioxides (NO₂), nitric oxide (NO), sulfur dioxide (SO₂) in standard deviations (SD)) at different early life stages with lung function (indicated by forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁) and forced expiratory flow at 25%-75% of the pulmonary volume (FEF_25%-75%)) in SD at ~17.5 years, personal history of wheezing and asthma in the population-representative Hong Kong Chinese birth cohort "Children of 1997"(n = 2942).

RESULTS

Higher in utero and infancy and toddlerhood NO₂ were associated with lower FEV₁ (-0.022, 95% confidence interval (CI) -0.029 to -0.015 and - 0.026, 95% CI -0.033 to -0.019), FEV₁/FVC (-0.035, 95% CI -0.050 to -0.021 and -0.052, 95% CI -0.066 to -0.038) and FEF_25%-75% (-0.031, 95% CI -0.040 to -0.022 and -0.043, 95% CI -0.051 to -0.035). A similar association was observed for NO. Weak associations of NO₂ and NO with FVC were observed (-0.011, 95% CI -0.018 to -0.003 and -0.010, 95% CI -0.020 to -0.001). NO_x was associated with higher risk of wheezing (1.08, 95% CI 1.03 to 1.14) but not asthma (1.02, 95% CI 0.94 to 1.11). SO₂ and PM₁₀ were not clearly associated with lung function, wheezing or asthma.

CONCLUSION

Our findings suggest that early exposure to air pollution from NO₂ may have long-term effects on lung function, which could affect respiratory health throughout life.

Glucose-6-phosphate dehydrogenase deficiency and metabolic profiling in adolescence from the Chinese birth cohort: "Children of 1997"

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) deficiency affects 6.0% of the global population. G6PD deficiency has been associated with lower risk of cardiovascular disease and higher risk of diabetes, which could be etiologically informative, but these relations are uncertain. To clarify, we assessed the associations of G6PD deficiency with serum metabolite profiles in late adolescence.

METHODS

In a nested case-control study of 50 G6PD-deficient late adolescents (~17.5 years) and 150 sex-matched non-G6PD-deficient controls from a Chinese birth cohort: "Children of 1997", we compared 80 serum metabolites analyzed by nuclear magnetic resonance spectrometry using adjusted linear regression with Bonferroni correction for testing 12 traits (p < 0.0042).

RESULTS

G6PD-deficiency was inversely associated with serum levels of total cholesterol (-0.27 mmol, 95% confidence interval (CI) -0.46, -0.09, p = 0.004), free cholesterol (-0.08 mmol, 95% CI -0.13, -0.03, p = 0.003) and creatinine (-0.004 mmol, 95% CI -0.007, -0.001, p = 0.003), adjusted for sex and parental education. G6PD deficiency was not associated with fatty acids, amino acids, glucose or related metabolites, ketone bodies or glycoprotein.

CONCLUSIONS

G6PD deficiency is associated with lower serum levels of cholesterol and creatinine, but not other serum metabolites. Whether such differences are transient or become more evident in adulthood warrant further investigations.

The role of social support in family socio-economic disparities in depressive symptoms during early pregnancy: Evidence from a Chinese birth cohort

BACKGROUND

Few studies have examined the association between a composite measure of family socio-economic position (SEP)² and depressive symptoms among Chinese pregnant women, nor any potential underlying mechanisms which may be amenable to preventative interventions.

METHODS

We investigated the association between a composite SEP measure and depressive symptoms during early pregnancy, and tested for mediation by social support and moderation by parity in the Born in Guangzhou Cohort Study (n = 12,382) using adjusted logistic regression and causal mediation analysis.

RESULTS

In this population, 18.4% of women experienced depressive symptoms before the 20th gestational week. Compared with the highest quartile, the lowest SEP score quartile was associated with a higher risk of depressive symptoms (OR 1.50, 95% CI 1.31-1.71), which was more pronounced among multiparous women than nulliparous women (P for interaction <0.001). Social support mediated the association between SEP and depressive symptoms, with greater proportion mediated in nulliparous women (73.4% for the lowest SEP score quartile) than multiparous women (30.5%).

LIMITATIONS

Depressive symptoms were measured by Self-rated Depression Scale, which is not designed as a clinical diagnosis tool for depression. We only had information on perceived social support but not actual social support, although these two parameters were modestly correlated.

CONCLUSION

Lower SEP was associated with higher risk of depressive symptoms in pregnant women, driven by social support. And the association between SEP and depressive symptoms and mediation by social support were modified by parity. Whether this association extends to the post pregnancy period or is amenable to cost-effective interventions should be investigated in further studies.

The Roles of 27 Genera of Human Gut Microbiota in Ischemic Heart Disease, Type 2 Diabetes Mellitus, and Their Risk Factors: A Mendelian Randomization Study

Manipulation of the gut microbiota presents a new opportunity to combat chronic diseases. Randomized controlled trials of probiotics suggest some associations with adiposity, lipids, and insulin resistance, but to our knowledge no trials with "hard" outcomes have been conducted. We used separate-sample Mendelian randomization to obtain estimates of the associations of 27 genera of gut microbiota with ischemic heart disease, type 2 diabetes mellitus, adiposity, lipid levels, and insulin resistance, based on summary data from CARDIoGRAAMplusC4D and other consortia. Among the 27 genera, a 1-allele increase in single nucleotide polymorphisms related to greater abundance of Bifidobacterium was associated with lower risk of ischemic heart disease (odds ratio = 0.985, 95% confidence interval (CI): 0.971, 1.000; P = 0.04), a 0.011-standard-deviation lower body mass index (95% CI: -0.017, -0.005), and a 0.026-standard-deviation higher low-density lipoprotein cholesterol level (95% CI: 0.019, 0.033), but the findings were not robust to exclusion of potential pleiotropy. We also identified Acidaminococcus, Aggregatibacter, Anaerostipes, Blautia, Desulfovibrio, Dorea, and Faecalibacterium as being nominally associated with type 2 diabetes mellitus or other risk factors. Results from our study indicate that these 8 genera of gut microbiota should be given priority in future research relating the gut microbiome to ischemic heart disease and its risk factors.

Augmented Reality Games as a New Class of Physical Activity Interventions? The Impact of Pokémon Go Use and Gaming Intensity on Physical Activity

OBJECTIVE

To assess the health impact of augmented reality games by examining the association between Pokémon Go and physical activity among university students.

MATERIALS AND METHODS

This pilot study included 65 medical students who were iPhone (Apple, Inc., Cupertino, CA) users with the built-in accelerometer and Health app. Main outcome measures were the change in daily walking distance before and after the release of Pokémon Go (Niantic, Inc., San Francisco, CA).

RESULTS

Twenty-four (36.9%) medical students were active Pokémon Go players. When compared with nonplayers, Pokémon Go players on average walked 1.5, 1.2, 0.9, and 0.6 km more daily on the third, fourth, fifth, and sixth day of the game, respectively (P < 0.05). Physical activity differences were not detected beyond the first week. Among Pokémon Go players, higher intensity of gaming was associated with increased distance walked 50 days after the release of the game compared to previously (P < 0.001).

CONCLUSIONS

In this pilot study, Pokémon Go was associated with a transient increase in physical activity in the first week. Augmented reality games need to demonstrate a sustained positive health impact to be promoted as a new class of physical activity interventions.

Simultaneously characterizing the comparative economics of routine female adolescent nonavalent human papillomavirus (HPV) vaccination and assortativity of sexual mixing in Hong Kong Chinese: a modeling analysis

BACKGROUND

Although routine vaccination of females before sexual debut against human papillomavirus (HPV) has been found to be cost-effective around the world, its cost-benefit has rarely been examined. We evaluate both the cost-effectiveness and cost-benefit of routine female adolescent nonavalent HPV vaccination in Hong Kong to guide its policy, and by extension that of mainland China, on HPV vaccination. One major obstacle is the lack of data on assortativity of sexual mixing. Such difficulty could be overcome by inferring sexual mixing parameters from HPV epidemiologic data.

METHODS

We use an age-structured transmission model coupled with stochastic individual-based simulations to estimate the health and economic impact of routine nonavalent HPV vaccination for girls at age 12 on cervical cancer burden and consider vaccine uptake at 25%, 50%, and 75% with at least 20 years of vaccine protection. Bayesian inference was employed to parameterize the model using local data on HPV prevalence and cervical cancer incidence. We use the human capital approach in the cost-benefit analysis (CBA) and GDP per capita as the indicative willingness-to-pay threshold in the cost-effectiveness analysis (CEA). Finally, we estimate the threshold vaccine cost (TVC), which is the maximum cost for fully vaccinating one girl at which routine female adolescent nonavalent HPV vaccination is cost-beneficial or cost-effective.

RESULTS

As vaccine uptake increased, TVC decreased (i.e., economically more stringent) in the CBA but increased in the CEA. When vaccine uptake was 75% and the vaccine provided only 20 years of protection, the TVC was US$444 ($373-506) and $689 ($646-734) in the CBA and CEA, respectively, increasing by approximately 2-4% if vaccine protection was assumed lifelong. TVC is likely to be far higher when non-cervical diseases are included. The inferred sexual mixing parameters suggest that sexual mixing in Hong Kong is highly assortative by both age and sexual activity level.

CONCLUSIONS

Routine HPV vaccination of 12-year-old females is highly likely to be cost-beneficial and cost-effective in Hong Kong. Inference of sexual mixing parameters from epidemiologic data of prevalent sexually transmitted diseases (i.e., HPV, chlamydia, etc.) is a potentially fruitful but largely untapped methodology for understanding sexual behaviors in the population.

Saving sight in China and beyond: the Lifeline Express model

Cataract and diabetic retinopathy are leading causes of blindness globally. Lifeline Express (LEX) has pioneered the provision of cataract surgery in rural China from custom-built trains and eye centres nationwide. Over the past two decades, LEX has provided free cataract surgery for over 180 000 patients in China. In China, half of the adult population has prediabetes and 113 million adults have diabetes. Recognising the rising threat of diabetic retinopathy, LEX has expanded to providing free diabetic retinopathy screening nationwide by establishing 29 Diabetic Retinopathy Screening Centres across China. Source of referrals included host hospitals, the community and out-reach mobile vans equipped with fundus cameras. Fundi photos taken in the mobile vans were electronically transferred to primary graders. LEX also leveraged the widespread smartphone use to provide electronic medical reports via WeChat, the most popular instant messenger app in China. From April 2014 to December 2016, 34 506 patients with diabetes underwent screening, of which 27.2% (9,396) were identified to have diabetic retinopathy. China's latest national health strategy ('Healthy China 2030 Plan') has championed the 'prevention first' principle and early screening of chronic diseases. LEX has accordingly evolved to extend its services to save sight in China-from cataract surgery to diabetic retinopathy screening and most recently outreaching beyond its national borders in a pilot South-South collaboration. With health at the top of the China's developmental agenda and the country's growing role in global health-LEX's large-scale telemedicine-enabled programme could represent a potentially scalable model for nationwide diabetic retinopathy screening elsewhere.

Behavioral problem trajectories and self-esteem changes in relation with adolescent depressive symptoms: a longitudinal study

PURPOSE

Prospectively childhood behavioral problems and low self-esteem are associated with depression. However, these mental health changes over time have never been examined. This study assessed the association of childhood behavioral trajectories and self-esteem changes over time with adolescent depressive symptoms.

METHODS

Parent-reported Rutter behavioral assessments and self-reported Culture-Free Self-Esteem Inventories (SEI) were obtained via record linkage from the Student Health Service, Department of Health (Hong Kong), and the Patient Health Questionnaire-9 (PHQ-9) depressive symptom scores were obtained via active follow-up of the Hong Kong's Children of 1997" Chinese birth cohort. Partitional clustering was used to generate homogenous trajectories between ~ 7 and ~ 11 years for Rutter scores. Changes in low self-esteem between ~ 10 and ~ 12 years were obtained from the SEI. Multiple linear regression was used to estimate their associations with depressive symptom scores at ~ 13 years.

RESULTS

Four trajectories/groups (stable low, declining, rising, and stable high) of Rutter score and self-esteem groups were created. The stable low behavioral trajectory was associated with the fewest depressive symptoms while the stable high trajectory had 1.23 more depressive symptoms [95% confidence interval (CI) 0.84 to 1.61] than the stable low trajectory. Consistently low self-esteem (stable low) was associated with 2.96 more depressive symptoms (95% CI 2.35-3.57) compared to consistently high self-esteem (stable high).

CONCLUSIONS

Sustained or worsening childhood behavioral problems and low self-esteem were precursors of adolescent depressive symptoms, and as such could be an early indicator of the need for intervention.

Epidemiology of hand, foot and mouth disease in China, 2008 to 2015 prior to the introduction of EV-A71 vaccine

Hand, foot and mouth disease (HFMD) is usually caused by several serotypes from human enterovirus A species, including enterovirus 71 (EV-A71) and coxsackievirus A16 (CV-A16). Two inactivated monovalent EV-A71 vaccines have been recently licensed in China and monovalent CV-A16 vaccine and bivalent EV-A71 and CV-A16 vaccine are under development. Methods: Using notifications from the national surveillance system, we describe the epidemiology and dynamics of HFMD in the country, before the introduction of EV-A71 vaccination, from 2008 through 2015. Results: Laboratory-identified serotype categories, i.e. CV-A16, EV-A71 and other enteroviruses, circulated annually. EV-A71 remained the most virulent serotype and was the major serotype for fatal cases (range: 88.5–95.4%) and severe cases (range: 50.7–82.3%) across years. Except for 2013 and 2015, when other enteroviruses were more frequently found in mild HFMD (48.8% and 52.5%), EV-A71 was more frequently detected from mild cases in the rest of the years covered by the study (range: 39.4–52.6%). The incidence rates and severity risks of HFMD associated with all serotype categories were the highest for children aged 1 year and younger, and decreased with increasing age. Discussion/conclusion: This study provides baseline epidemiology for evaluation of vaccine impact and potential serotype replacement.

In utero exposure to gestational diabetes and adiposity: does breastfeeding make a difference?

BACKGROUND/OBJECTIVES

Short-term breastfeeding from mothers with gestational diabetes (GDM) may programme metabolism and increase offspring diabetes risk. We examined the association of in utero GDM exposure with adiposity from infancy to adolescence, and whether any association was modified by breastfeeding during early infancy.

METHODS

In the prospective Chinese birth cohort "Children of 1997" (n = 7342, 88% follow-up rate), generalised estimate equations with multiple imputation were used to assess associations of in utero GDM exposure with age- and sex-specific body mass index (BMI) z-score during infancy (3 and 9 months), childhood (2- < 8 years) and adolescence (8-16 years), adjusted for sex, parity, maternal age, birth place, preeclampisa, smoking, and family socio-economic position. We also tested whether the associations differed by mode of infant feeding (always formula-fed, mixed, always breastfed) during the first three months of life.

RESULTS

In utero GDM exposure (7.5%) was associated with a lower BMI z-score during infancy (-0.13, 95% confidence interval (CI) -0.22, -0.05) but higher BMI z-scores during childhood (0.14, 95% CI 0.03, 0.25) and adolescence (0.25 95% CI 0.11, 0.38). Breastfeeding for the first three months did not modify the association of in utero GDM status with subsequent BMI (all p values for interaction >0.4).

CONCLUSIONS

In utero GDM exposure was associated with greater adiposity during childhood and adolescence. Breastfeeding in early infancy from mothers with GDM was not associated with greater adiposity in children and thus should still be encouraged.

Preliminary Epidemiologic Assessment of Human Infections With Highly Pathogenic Avian Influenza A(H5N6) Virus, China

Background

Since 2014, 17 human cases of infection with the newly emerged highly pathogenic avian influenza A(H5N6) virus have been identified in China to date. The epidemiologic characteristics of laboratory-confirmed A(H5N6) cases were compared to A(H5N1) and A(H7N9) cases in mainland China.

Methods

Data on laboratory-confirmed H5N6, H5N1, and H7N9 cases identified in mainland China were analyzed to compare epidemiologic characteristics and clinical severity. Severity of confirmed H5N6, H5N1 and H7N9 cases was estimated based on the risk of severe outcomes in hospitalized cases.

Results

H5N6 cases were older than H5N1 cases with a higher prevalence of underlying medical conditions but younger than H7N9 cases. Epidemiological time-to-event distributions were similar among cases infected with the 3 viruses. In comparison to a fatality risk of 70% (30/43) for hospitalized H5N1 cases and 41% (319/782) for hospitalized H7N9 cases, 12 (75%) out of the 16 hospitalized H5N6 cases were fatal, and 15 (94%) required mechanical ventilation.

Conclusion

Similar epidemiologic characteristics and high severity were observed in cases of H5N6 and H5N1 virus infection, whereas severity of H7N9 virus infections appeared lower. Continued surveillance of human infections with avian influenza A viruses remains an essential component of pandemic influenza preparedness.

Cohort Profile: FAMILY Cohort

The FAMILY Cohort is a longitudinal study of health, happiness and family harmony (the '3Hs') at individual, household and neighbourhood levels in Hong Kong. Using a family living in the same household as the sampling unit, the study (n = 20 279 households and 46 001 participants) consists of a composite sample from several sources, including: a population-representative random core sample (n = 8115 households and 19 533 participants); the first-degree relatives of this sample (n = 4658 households and 11 063 participants); and oversampling in three new towns (n = 2891 households and 7645 participants) and in three population subgroups with anticipated changes in family dynamics (n = 909 households and 2160 participants). Two household visits and five telephone- or web-based follow-ups were conducted over 2009-14. Data collected include socio-demographics, anthropometrics, lifestyle and behavioural factors, measures of social capital, and standardized instruments assessing the 3Hs. We also intend to collect biomaterials in future. The analytical plan includes multilevel inter-relations of the 3Hs for individuals, households, extended families and neighbourhoods. With Hong Kong's recent history of socioeconomic development, the FAMILY Cohort is therefore relevant to global urban populations currently experiencing similarly rapid economic growth. The FAMILY Cohort is currently set up as a supported access resource.

The Associations of Breast Feeding with Infant Growth and Body Mass Index to 16 years: 'Children of 1997'

BACKGROUND

Controversial findings concerning associations of breast feeding with growth have been reported. This study examined whether the associations of breast feeding with early growth trajectories and body mass index to 16 years differed by sex or age.

METHODS

In Hong Kong's 'Children of 1997' population-representative birth cohort, contemporaneously reported breast-feeding status in the first 3 months was classified as exclusive breast feeding (BF) (n = 470), mixed feeding (MF) (n = 2693), and formula feeding (FF) (n = 4204). Adjusted sex- and age-specific associations of breast feeding with infant growth (gains in weight-for-age z scores (WAZ), length/height-for-age z scores (LAZ), and body-mass-index-for-age z score (BAZ) based on the World Health Organization standards/references from birth to 36 months) were assessed using linear regression and mixed modelling, respectively. Adjusted sex-specific associations of breast feeding with average BAZ from 3 months to 16 years were assessed using generalized estimating equation. Potential confounders were maternal and infant characteristics, and household income.

RESULTS

Among 7367 children, associations of breast feeding with infant growth did not vary by sex, but WAZ gains varied by age. Greater WAZ gains were observed in BF than FF infants from 0 to 3 months but in FF than BF infants from 3 to 9 months. Breast feeding was not associated with overall BAZ from 3 months to 16 years, with no differences by sex.

CONCLUSIONS

Our findings suggest that breast feeding may only have short-term effects on growth. Further studies of the role of breast feeding in other metabolic diseases may be needed.

Human Infection with Influenza A(H7N9) Virus during 3 Major Epidemic Waves, China, 2013-2015

Variation in risk for death might be associated with differences in case ascertainment, changes in clinical management, or virus genetic diversity.

Since March 2013, a novel influenza A(H7N9) virus has caused 3 epidemic waves of human infection in mainland China. We analyzed data from patients with laboratory-confirmed influenza A(H7N9) virus infection to estimate the risks for severe outcomes after hospitalization across the 3 waves. We found that hospitalized patients with confirmed infections in waves 2 and 3 were younger and more likely to be residing in small cities and rural areas than were patients in wave 1; they also had a higher risk for death, after adjustment for age and underlying medical conditions. Risk for death among hospitalized patients during waves 2 and 3 was lower in Jiangxi and Fujian Provinces than in eastern and southern provinces. The variation in risk for death among hospitalized case-patients in different areas across 3 epidemic waves might be associated with differences in case ascertainment, changes in clinical management, or virus genetic diversity.

The Association of Intergenerational Mismatch With Adiposity and Blood Pressure in Childhood and Adolescence

PURPOSE

An intergenerational "mismatch," a transition from limited to plentiful living conditions over generations, may increase cardiovascular disease risks. In a migrant population within a homogenous culture, we tested the hypothesis that an intergenerational mismatch in childhood living condition is associated with higher body mass index (BMI) and blood pressure in childhood and adolescence.

METHODS

We used data from 6,965 native born Chinese in Hong Kong (participated in "Children of 1997" birth cohort) and migrant Chinese born elsewhere in China in 1997 (N = 9,845). We classified children into those with intergenerational mismatch (child migrants or first-generation migrants) or those without (second+-generation migrants). Generalized estimating equations were used to examine the associations of migration status (child migrants, first-generation migrants or second+-generation migrants) with age- and sex-specific BMI z-score at 8-15 years and age-, sex-, and height-specific blood pressure z-score at 11-13 years, adjusted for sex, month of birth, and age.

RESULTS

Compared with second+-generation migrants, first-generation migrants had higher diastolic blood pressure z-score (.04, 95% confidence interval (CI) .02, .06) and BMI z-score (.12, 95% CI .06, .18), whereas child migrants had higher diastolic blood pressure z-score (.03, 95% CI .01, .05) regardless of age at migration and higher BMI z-score if they had migrated in infancy (.17, 95% CI .11, .23).

CONCLUSION

Different relations for blood pressure and BMI suggest that intergenerational mismatch and proximal exposures may have different impacts on adiposity and blood pressure.

Viral Shedding and Transmission Potential of Asymptomatic and Paucisymptomatic Influenza Virus Infections in the Community

Background

Influenza virus infections are associated with a wide spectrum of disease. However, few studies have investigated in detail the epidemiological and virological characteristics of asymptomatic and mild illness with influenza virus infections.

Methods

In a community-based study in Hong Kong from 2008 to 2014, we followed up initially healthy individuals who were household contacts of symptomatic persons with laboratory-confirmed influenza, to identify secondary infections. Information from daily symptom diaries was used to classify infections as symptomatic (≥2 signs/symptoms, including fever ≥37.8°C, headache, myalgia, cough, sore throat, runny nose and sputum), paucisymptomatic (1 symptom only), or asymptomatic (none of these symptoms). We compared the patterns of influenza viral shedding between these groups.

Results

We identified 235 virologically confirmed secondary cases of influenza virus infection in the household setting, including 31 (13%) paucisymptomatic and 25 (11%) asymptomatic cases. The duration of viral RNA shedding was shorter and declined more rapidly in paucisymptomatic and asymptomatic than in symptomatic cases. The mean levels of influenza viral RNA shedding in asymptomatic and paucisymptomatic cases were approximately 1-2 log10 copies lower than in symptomatic cases.

Conclusions

The presence of influenza viral shedding in patients with influenza who have very few or no symptoms reflects their potential for transmitting the virus to close contacts. These findings suggest that further research is needed to investigate the contribution of persons with asymptomatic or clinically mild influenza virus infections to influenza virus transmission in household, institutional, and community settings.

Mode of delivery and child and adolescent psychological well-being: Evidence from Hong Kong's "Children of 1997" birth cohort

Mode of delivery (vaginal or cesarean section) is thought to affect gut microbiota, which in turn may affect psychological well-being. As such, mode of delivery is potentially a modifiable factor for psychological well-being. Here we examined the association of mode of delivery with child and adolescent psychological well-being. We used multivariable linear regression in a population-representative Hong Kong Chinese birth cohort, “Children of 1997,” to examine the adjusted associations of mode of delivery with behavioral problems assessed from parent-reported Rutter score at ~7 (n = 6294) and ~11 years (n = 5598), self-esteem assessed from self-reported Culture-Free Self-Esteem Inventory score at ~11 years (n = 6937) and depressive symptoms assessed from self-reported Patient Health Questionnaire-9 score at ~13 years (n = 5797). Cesarean Section (CS) was associated with children born in private hospitals, boys, and firstborns, higher maternal body mass index, higher maternal age, preeclampsia, higher socioeconomic position (SEP) and maternal birth in Hong Kong. CS was unrelated to behavior, self-esteem and depressive symptoms adjusted for infant characteristics (sex, gestational age, birthweight, parity and breast feeding), maternal characteristics (mother’s age and place of birth) and SEP. In a developed non-Western setting, mode of delivery was not clearly associated with childhood or early adolescent psychological well-being.

A Smart Card-Based Electronic School Absenteeism System for Influenza-Like Illness Surveillance in Hong Kong: Design, Implementation, and Feasibility Assessment

Background

School-aged children have the highest incidence of respiratory virus infections each year, and transmission of respiratory viruses such as influenza virus can be a major concern in school settings. School absenteeism data have been employed as a component of influenza surveillance systems in some locations. Data timeliness and system acceptance remain as key determinants affecting the usefulness of a prospective surveillance system.

Objective

The aim of this study was to assess the feasibility of implementing an electronic school absenteeism surveillance system using smart card–based technology for influenza-like illness (ILI) surveillance among a representative network of local primary and secondary schools in Hong Kong.

Methods

We designed and implemented a surveillance system according to the Protocol for a Standardized information infrastructure for Pandemic and Emerging infectious disease Response (PROSPER). We employed an existing smart card–based education and school administration platform for data capture, customized the user interface, and used additional back end systems built for other downstream surveillance steps. We invited local schools to participate and collected absenteeism data by the implemented system. We compared temporal trend of the absenteeism data with data from existing community sentinel and laboratory surveillance data.

Results

We designed and implemented an ILI surveillance system utilizing smart card–based attendance tracking approach for data capture. We implemented the surveillance system in a total of 107 schools (including 66 primary schools and 41 secondary schools), covering a total of 75,052 children. The system successfully captured information on absences for 2 consecutive academic years (2012-2013 and 2013-2014). The absenteeism data we collected from the system reflected ILI activity in the community, with an upsurge in disease activity detected up to 1 to 2 weeks preceding other existing surveillance systems.

Conclusions

We designed and implemented a novel smart card technology–based school absenteeism surveillance system. Our study demonstrated the feasibility of building a large-scale surveillance system riding on a routinely adopted data collection approach and the use of simple system enhancement to minimize workload implication and enhance system acceptability. Data from this system have potential value in supplementing existing sentinel influenza surveillance for situational awareness of influenza activity in the community.

Pathways from parental educational attainment to adolescent blood pressure

OBJECTIVES

Lower parental education is associated with higher adolescent blood pressure (BP). We examined the contribution of modifiable risk factors from infancy to adolescence that could potentially explain the link between parental education and SBP and DBP in the offspring.

METHODS

In a prospective Chinese birth cohort, 'Children of 1997' of 5604 adolescents (68% follow-up), we analyzed the relation between parental educational attainment and sex-specific, age-specific and height-specific BP z-scores at ∼13 years. Using mediation analysis, we examined the contribution of household income at birth (both absolute income and relative income deprivation), exposures during infancy (breastfeeding and early life second-hand smoking), lifestyles during childhood (diet, physical activity and screen-time), weight or BMI status during fetal, infancy, childhood and puberty, pubertal stage as well as parental BMI.

RESULTS

We found that adolescent BMI, but not birth weight or infant growth or childhood BMI, mediated the inverse association of parental education with adolescent SBP (proportion mediated: 24%), followed by maternal BMI (proportion mediated: 18%). Factors explaining the link between parental education and DBP were less clear. Absolute income, breastfeeding, childhood diet and physical activity, pubertal stage and paternal BMI did not mediate the association between parental education and adolescent BP.

CONCLUSION

Low parental education is a risk factor for high SBP and, to a lesser extent, DBP in adolescents. Important mediators of this relation include adolescent and maternal body weight.

The association of air pollution with birthweight and gestational age: evidence from Hong Kong's 'Children of 1997' birth cohort

Background

Previous studies from Western settings have found inconsistent associations of air pollutants with birth outcomes, which are open to residual confounding by socioeconomic position (SEP). We assessed this association in the economically developed non-Western setting of Hong Kong, with high levels of air pollution but little social patterning of these outcomes.

Methods

We obtained PM10, SO2, NO and NO2 from monitoring stations, and assessed their associations with birthweight and gestational age in a large population-representative birth cohort 'Children of 1997', using partial least-square regression to account for the colinearity between pollutants.

Results

PM10 (per 5.7 µg/m3 higher) and NO2 (per 10.9 µg/m3 higher) were associated with birthweight lower by 47.0 g (95% confidence interval (CI) 36.2-56.3) and 16.9 g (95% CI 10.8-22.6), respectively; and were associated with gestational age shorter by 2.1 days (95% CI 1.7-2.4) and 0.7 days (95% CI 0.5-0.8), respectively.

Conclusions

Given minimal confounding by SEP in our setting, these findings provide unequivocal evidence of adverse effects of PM10 and NO2 exposure during pregnancy on birthweight and gestational age. Physiological mechanisms need to be better understood to support effective public health action globally.

The association of breastfeeding with insulin resistance at 17 years: Prospective observations from Hong Kong's "Children of 1997" birth cohort

Breastfeeding has many benefits for mother and infant. Whether breastfeeding also protects against type 2 diabetes is unclear. To clarify the role of breastfeeding in type 2 diabetes, we assessed the association of breastfeeding with insulin resistance in late adolescence in a birth cohort from a non-Western setting where breastfeeding was not associated with higher socio-economic position. We used multivariable linear regression, with multiple imputation and inverse probability weighting, to examine the adjusted associations of contemporaneously reported feeding in the first 3 months of life (exclusively breastfed, mixed feeding, or always formula-fed) with fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) at 17 years in a subset (n = 710, 8.6% of entire cohort) of the Hong Kong Chinese birth cohort "Children of 1997." We found a graded association of breastfeeding exclusivity in the first 3 months of life with lower fasting insulin and HOMA-IR (p-for-trend < .05), but not fasting glucose, at 17 years. Exclusively breastfed adolescents (7%) had nonsignificantly lowest fasting insulin and HOMA-IR, adjusted for sex, birth weight, parity, length of gestation, pregnancy characteristics, parents' education, and mother's place of birth. Exclusively breastfeeding for 3 months may be causally associated with lower insulin resistance in late adolescence. Further follow-up studies into adulthood are required to clarify the long-term protection of breastfeeding from type 2 diabetes.

Diabetes incidence and prevalence in Hong Kong, China during 2006-2014

AIMS

To estimate recent secular changes in the incidence and prevalence of diabetes and pre-diabetes among Hong Kong Chinese adults, and thus show possible future trends for developing mainland China.

METHODS

Based on a complete census of the public sector health records of 6.4 million people from 2006 to 2014, diabetes cases were ascertained using different methods including the World Health Organization (WHO) 2011 guidelines (HbA_1c , fasting plasma glucose and glucose tolerance test), American Diabetes Association (ADA) 2015 guidelines (plus random plasma glucose), and additionally recorded diagnosis codes and medication dispensation. Pre-diabetes was defined using ADA 2015 guidelines.

RESULTS

We identified 697 201 people with diabetes (54.2% were incident cases); and 1 229 731 people with diabetes or pre-diabetes. In 2014, the overall incidence of diabetes was 9.46 per 1000 person-years [95% confidence interval (CI): 9.38 to 9.54], and overall prevalence was 10.29% (95% CI: 10.27% to 10.32%). Incidence of diabetes decreased significantly from 2007 to 2014 (quadratic trend, P < 0.001). From 2006 to 2014, the prevalence of diabetes increased significantly in both sexes and across all age groups (quadratic trend, P < 0.001). The overall incidence of pre-diabetes in 2014 was 18.88 per 1000 person-years (95% CI: 18.76 to 18.99), and the overall prevalence of pre-diabetes was 8.90% (95% CI: 8.87% to 8.92%).

CONCLUSIONS

Similar to other developed western and Asian populations, diabetes (and pre-diabetes) incidence in Hong Kong Chinese appeared to have stabilized and there have been small declines during the period of observation. Ageing and survivorship will likely drive a continued increase in the prevalence of diabetes and pre-diabetes, albeit with a decelerating growth rate if past trends persist.

Epidemiology of avian influenza A H7N9 virus in human beings across five epidemics in mainland China, 2013-17: an epidemiological study of laboratory-confirmed case series

BACKGROUND

The avian influenza A H7N9 virus has caused infections in human beings in China since 2013. A large epidemic in 2016-17 prompted concerns that the epidemiology of the virus might have changed, increasing the threat of a pandemic. We aimed to describe the epidemiological characteristics, clinical severity, and time-to-event distributions of patients infected with A H7N9 in the 2016-17 epidemic compared with previous epidemics.

METHODS

In this epidemiological study, we obtained information about all laboratory-confirmed human cases of A H7N9 virus infection reported in mainland China as of Feb 23, 2017, from an integrated electronic database managed by the China Center for Disease Control and Prevention (CDC) and provincial CDCs. Every identified human case of A H7N9 virus infection was required to be reported to China CDC within 24 h via a national surveillance system for notifiable infectious diseases. We described the epidemiological characteristics across epidemics, and estimated the risk of death, mechanical ventilation, and admission to the intensive care unit for patients admitted to hospital for routine clinical practice rather than for isolation purpose. We estimated the incubation periods, and time delays from illness onset to hospital admission, illness onset to initiation of antiviral treatment, and hospital admission to death or discharge using survival analysis techniques.

FINDINGS

Between Feb 19, 2013, and Feb 23, 2017, 1220 laboratory-confirmed human infections with A H7N9 virus were reported in mainland China, with 134 cases reported in the spring of 2013, 306 in 2013-14, 219 in 2014-15, 114 in 2015-16, and 447 in 2016-17. The 2016-17 A H7N9 epidemic began earlier, spread to more districts and counties in affected provinces, and had more confirmed cases than previous epidemics. The proportion of cases in middle-aged adults increased steadily from 41% (55 of 134) to 57% (254 of 447) from the first epidemic to the 2016-17 epidemic. Proportions of cases in semi-urban and rural residents in the 2015-16 and 2016-17 epidemics (63% [72 of 114] and 61% [274 of 447], respectively) were higher than those in the first three epidemics (39% [52 of 134], 55% [169 of 306], and 56% [122 of 219], respectively). The clinical severity of individuals admitted to hospital in the 2016-17 epidemic was similar to that in the previous epidemics.

INTERPRETATION

Age distribution and case sources have changed gradually across epidemics since 2013, while clinical severity has not changed substantially. Continued vigilance and sustained intensive control efforts are needed to minimise the risk of human infection with A H7N9 virus.

FUNDING

The National Science Fund for Distinguished Young Scholars.

The Association of Air Pollution With Pubertal Development: Evidence From Hong Kong's "Children of 1997" Birth Cohort

Many pollutants are endocrine disruptors with impacts on reproduction and health in animals, but evidence in humans, of which sex-specific effects on pubertal development may be an indicator, is less clear. We examined the association of air pollution in utero and during early life with pubertal development in Hong Kong, China, an area with a high level of air pollution compared with other similarly developed cities. We assessed sex-specific associations of particulate matter less than or equal to 10 μm in diameter (PM10), nitric oxide, sulfur dioxide, and nitrogen dioxide in different growth phases with clinically assessed pubertal stage at approximately age 11 years (as indicated by Tanner stage) in a large population-representative birth cohort, the "Children of 1997." We used partial least squares regression to account for colinearity between air pollutants. Among 1,938 girls, PM10 exposure in utero and during infancy was negatively associated with pubertal stage and breast development, whereas among 2,136 boys, sulfur dioxide and nitrogen dioxide exposure in utero, during infancy, and in childhood were negatively associated with pubertal stage. These sex-specific associations with pubertal development are consistent with endocrine-disrupting effects. Given the health impact of altered pubertal timing, further investigation across the life course may help quantify the full effects and the corresponding need for preventive measures.

Migrant status and childhood hospitalizations for asthma and other wheezing disorders

BACKGROUND

In developed Western settings, asthma is more prevalent among second-generation compared to first-generation migrants. However, these studies are difficult to interpret as they include migrants of various ethnicities and countries of origin.

OBJECTIVE

We assessed the association of parental migrant status with wheezing disorders among children born in Hong Kong, a developed non-Western setting, where many children have migrant parents from mainland China of the same ethnicity.

METHODS

We used Cox regression to examine the adjusted associations of parental migrant status with time to first public hospital admission for asthma, bronchitis and bronchiolitis (International Classification of Diseases, Ninth Version Clinical Modification 466, 490 and 493) from 9 days to 12 years in a population-representative birth cohort of 8327 Chinese children in Hong Kong.

RESULTS

Having both parents as migrants was associated with higher risk of hospitalization for asthma and other wheezing disorders, compared to both parents being Hong Kong born (hazard ratio 1.30, 95% confidence interval 1.05-1.60 from 9 days to 6 years), adjusted for type of hospital at birth, parental history of allergies, mother's age at birth, father's age at birth and highest parental education.

CONCLUSIONS AND CLINICAL RELEVANCE

In the unique, non-Western context of Hong Kong, second-generation migrants had higher risk of hospitalization for childhood wheezing disorders compared to the native population, particularly before 6 years of age. Further study is required to clarify the underlying mechanisms involved.

Pubertal testis volume, age at pubertal onset, and adolescent blood pressure: Evidence from Hong Kong's "Children of 1997" birth cohort

OBJECTIVES

A warning from Health Canada suggests that testosterone increases blood pressure (BP). No evidence from large randomized controlled trials is available, and observational studies are confounded by ill-health lowering serum testosterone. To address the evidence gap, we assessed the association of pubertal testicular volume, as a reflection of testosterone production, with BP.

METHODS

We examined whether testicular volume was associated with sex-, age-, and height-standardized BP z-score at ∼13 years in a population-representative Chinese birth cohort (n = 5195, 63% follow-up). We used age at pubertal onset, determined as the earliest age when Tanner stage II for genitalia, breast, or pubic hair, or testicular volume of 4 mL occurred, as control exposures. These exposures were expected to produce findings different from testicular volume because they are not direct measures of testosterone. They were used to ascertain specificity of exposure and to detect residual confounding.

RESULTS

Greater testicular volume was associated with higher systolic BP by 0.03 z-score, which is equivalent to 1.40 mm Hg per standard deviation of testicular volume (95% CI 0.02-0.04), adjusted for infant characteristics, socioeconomic position, and childhood body mass index. Similarly adjusted, earlier pubertal onset was not associated with higher systolic BP z-score in boys or girls.

CONCLUSIONS

Greater pubertal testicular volume is related to higher BP, consistent with a potential role of androgens in the higher BP in boys than girls that emerges during puberty. Our finding provides preliminary evidence supportive of more definitive studies to clarify the warning on testosterone from Health Canada.

Requesting a unique personal identifier or providing a souvenir incentive did not affect overall consent to health record linkage: evidence from an RCT nested within a cohort

OBJECTIVE

It is unclear if unique personal identifiers should be requested from participants for health record linkage: this permits high-quality data linkage but at the potential cost of lower consent rates due to privacy concerns.

STUDY DESIGN AND SETTING

Drawing from a sampling frame based on the FAMILY Cohort, using a 2 × 2 factorial design, we randomly assigned 1,200 participants to (1) request for Hong Kong Identity Card number (HKID) or no request and (2) receiving a souvenir incentive (valued at USD4) or no incentive. The primary outcome was consent to health record linkage. We also investigated associations between demographics, health status, and postal reminders with consent.

RESULTS

Overall, we received signed consent forms from 33.3% (95% confidence interval [CI] 30.6-36.0%) of respondents. We did not find an overall effect of requesting HKID (-4.3%, 95% CI -9.8% to 1.2%) or offering souvenir incentives (2.4%, 95% CI -3.1% to 7.9%) on consent to linkage. In subgroup analyses, requesting HKID significantly reduced consent among adults aged 18-44 years (odds ratio [OR] 0.53, 95% CI 0.30-0.94, compared to no request). Souvenir incentives increased consent among women (OR 1.55, 95% CI 1.13-2.11, compared to no souvenirs).

CONCLUSIONS

Requesting a unique personal identifier or providing a souvenir incentive did not affect overall consent to health record linkage.

Fractional dosing of yellow fever vaccine to extend supply: a modelling study

BACKGROUND

The ongoing yellow fever epidemic in Angola strains the global vaccine supply, prompting WHO to adopt dose sparing for its vaccination campaign in Kinshasa, Democratic Republic of the Congo, in July-August, 2016. Although a 5-fold fractional-dose vaccine is similar to standard-dose vaccine in safety and immunogenicity, efficacy is untested. There is an urgent need to ensure the robustness of fractional-dose vaccination by elucidation of the conditions under which dose fractionation would reduce transmission.

METHODS

We estimate the effective reproductive number for yellow fever in Angola using disease natural history and case report data. With simple mathematical models of yellow fever transmission, we calculate the infection attack rate (the proportion of population infected over the course of an epidemic) with various levels of transmissibility and 5-fold fractional-dose vaccine efficacy for two vaccination scenarios, ie, random vaccination in a hypothetical population that is completely susceptible, and the Kinshasa vaccination campaign in July-August, 2016, with different age cutoff for fractional-dose vaccines.

FINDINGS

We estimate the effective reproductive number early in the Angola outbreak was between 5·2 and 7·1. If vaccine action is all-or-nothing (ie, a proportion of vaccine recipients receive complete protection [VE] and the remainder receive no protection), n-fold fractionation can greatly reduce infection attack rate as long as VE exceeds 1/n. This benefit threshold becomes more stringent if vaccine action is leaky (ie, the susceptibility of each vaccine recipient is reduced by a factor that is equal to the vaccine efficacy). The age cutoff for fractional-dose vaccines chosen by WHO for the Kinshasa vaccination campaign (2 years) provides the largest reduction in infection attack rate if the efficacy of 5-fold fractional-dose vaccines exceeds 20%.

INTERPRETATION

Dose fractionation is an effective strategy for reduction of the infection attack rate that would be robust with a large margin for error in case fractional-dose VE is lower than expected.

FUNDING

NIH-MIDAS, HMRF-Hong Kong.

Glucose-6-Phosphate Dehydrogenase Deficiency and Physical and Mental Health until Adolescence

Background

To examine the association of glucose-6-phosphate dehydrogenase (G6PD) deficiency with adolescent physical and mental health, as effects of G6PD deficiency on health are rarely reported.

Methods

In a population-representative Chinese birth cohort: “Children of 1997” (n = 8,327), we estimated the adjusted associations of G6PD deficiency with growth using generalized estimating equations, with pubertal onset using interval censored regression, with hospitalization using Cox proportional hazards regression and with size, blood pressure, pubertal maturation and mental health using linear regression with multiple imputation and inverse probability weighting.

Results

Among 5,520 screened adolescents (66% follow-up), 4.8% boys and 0.5% girls had G6PD deficiency. G6PD-deficiency was not associated with birth weight-for-gestational age or length/height gain into adolescence, but was associated with lower childhood body mass index (BMI) gain (-0.38 z-score, 95% confidence interval (CI) -0.57, -0.20), adjusted for sex and parental education, and later onset of pubic hair development (time ratio = 1.029, 95% CI 1.007, 1.050). G6PD deficiency was not associated with blood pressure, height, BMI or mental health in adolescence, nor with serious infectious morbidity until adolescence.

Conclusions

G6PD deficient adolescents had broadly similar physical and mental health indicators, but transiently lower BMI gain and later pubic hair development, whose long-term implications warrant investigation.

Direct Participation in and Indirect Exposure to the Occupy Central Movement and Depressive Symptoms: A Longitudinal Study of Hong Kong Adults

Despite the extensive history of social movements around the world, the evolution of population mental health before, during, and after a social movement remains sparsely documented. We sought to assess over time the prevalence of depressive symptoms during and after the Occupy Central movement in Hong Kong and to examine the associations of direct and indirect exposures to Occupy Central with depressive symptoms. We longitudinally administered interviews to 909 adults who were randomly sampled from the population-representative FAMILY Cohort at 6 time points from March 2009 to March 2015: twice each before, during, and after the Occupy Central protests. The Patient Health Questionnaire-9 was used to assess depressive symptoms and probable major depression (defined as Patient Health Questionnaire-9 score ≥10). The absolute prevalence of probable major depression increased by 7% after Occupy Central, regardless of personal involvement in the protests. Higher levels of depressive symptoms were associated with online and social media exposure to protest-related news (incidence rate ratio (IRR) = 1.28, 95% confidence interval (CI): 1.06, 1.55) and more frequent Facebook use (IRR = 1.38, 95% CI: 1.12, 1.71). Higher levels of intrafamilial sociopolitical conflict was associated with more depressive symptoms (IRR = 1.05, 95% CI: 1.01, 1.09). The Occupy Central protests resulted in substantial and sustained psychological distress in the community.

Grandparental education, parental education and adolescent blood pressure

BACKGROUND

Maternal and paternal education could affect childhood blood pressure differently. Grandparental education might also play a role. Disentangling their contribution to childhood blood pressure may shed light on the persistence of disparities and potential windows of intervention.

METHODS

Using 5604 participants from a Chinese birth cohort born in 1997 and followed-up until ~13years (68% of follow-up), we examined the associations of parental education and grandparental education with age-, sex, and height-specific blood pressure z-scores or prehypertension status.

RESULTS

Parental education was inversely associated with adolescent systolic (-0.11 z-score, equivalent to -1.17mmHg, 95% confidence interval (CI) -0.19 to -0.04 for grade ≥12 compared with grade ≤9) and diastolic blood pressure (-0.07 z-score, equivalent to -0.79mmHg, 95% CI -0.11 to -0.04). The magnitude of association was similar for maternal or paternal education. Grandparental education was not associated with adolescent blood pressure. No association with prehypertension was found.

CONCLUSIONS

In an economically developed non-Western setting, both maternal and paternal, but not grandparental, education was associated with adolescent blood pressure. Blood pressure may be responsive to contemporary family socioeconomic conditions that may be scrutinized for suitable interventions.

Stress across the life course and depression in a rapidly developing population: the Guangzhou Biobank Cohort Study

OBJECTIVE

The objective of this study was to examine the role of stress across the life course in the development of depression among older adults in a non-Western developing setting.

METHODS

Multivariable linear and multinomial logistic regression were used in cross-sectional analyses of 9729 Chinese participants (mean age 60.2 years) from phase 3 of the Guangzhou Biobank Cohort Study (2006-2008) to investigate the association of childhood adversities and adulthood stressors with depression.

RESULTS

Childhood adversities were associated with mild depression (odds ratio (OR) 1.78, 95% confidence interval (CI) 1.58, 2.02) and moderate-to-severe depression (OR 2.30, 95% CI 1.68, 3.15), adjusted for age, sex, education and childhood socio-economic status. Past-year adulthood stressors were also associated with mild depression (OR 1.96, 95% CI 1.54, 2.02) and moderate-to-severe depression (OR 3.55, 95% CI 2.21, 5.68), adjusting additionally for occupation and income. Adulthood stressors were more strongly associated with depressive symptoms among individuals with a history of childhood adversities.

CONCLUSIONS

Childhood adversities and adulthood stressors were independently associated with an increased risk of depression among older ambulatory adults, although adulthood stressors were more strongly associated with depression following exposure to childhood adversities. This is consistent with evidence from Western settings in which the social context of risk and protective factors for depression may differ and implies that the role of stress in the aetiology of depression is not context specific.

Age at Onset of Puberty and Adolescent Depression: "Children of 1997" Birth Cohort

OBJECTIVE

Timing of onset of puberty has fallen, with profound and detrimental consequences for health. We examined the associations of earlier onset of puberty with the presence of depression in early to middle adolescence.

METHODS

The study examined prospective adjusted associations of age at onset of puberty, based on clinically assessed Tanner stage for breast/genitalia and pubic hair development, and self-reported presence of depression, assessed from the 9-item Patient Health Questionnaire on average at 13.6 years (n = 5795 [73%]). These factors were examined by using multivariable logistic regression in a population-representative Hong Kong Chinese birth cohort (ie, the "Children of 1997"). We also assessed whether associations varied according to gender.

RESULTS

Association of age at onset of breast/genitalia development with the presence of depression varied according to gender. Earlier onset of breast development was associated with higher risk of the presence of depression (odds ratio, 0.83 per 1 year increase in age of onset [95% confidence interval, 0.70 to 0.98]) adjusted for age, socioeconomic position, mother's place of birth, birth order, secondhand smoke exposure, parental age, survey mode, gender-specific birth weight z score, BMI z score at 7 years, and parental marital status. In boys, similarly adjusted, age at onset of genitalia development was unrelated to the presence of depression. Earlier age at onset of pubic hair development was unrelated to the presence of depression in girls and boys.

CONCLUSIONS

Early onset of breast development was associated with high risk of the presence of depression. Whether these findings are indicators of the effects of hormones or transient effects of social pressures remain to be determined.

Population Behavior Patterns in Response to the Risk of Influenza A(H7N9) in Hong Kong, December 2013-February 2014

Background

A novel avian influenza A(H7N9) virus, first identified in Mainland China in February and March 2013, caused an outbreak in humans in April and May, 2013. Closure of live poultry markets in some affected cities dramatically reduced numbers of cases during summer of 2013, but the epidemic resurged during the winter 2013–14, increasing reported cases to 393 in Mainland China as of 30 March 2014.

Purpose

The study aimed to explore population behavior patterns responding to an epidemic of influenza A(H7N9) virus.

Method

Three cross-sectional surveys were conducted among 1000, 680, and 1011 respondents in December 2013, January 2014, and February 2014, with response rates of 68.0, 64.4, and 66.6 %, respectively, in Hong Kong. Adults were recruited and interviewed using random digit-dialing telephone survey. Latent class analysis was employed to explore heterogeneity in protective behavior patterns across the three surveys. Multinomial regression models were developed to determine factors associated with latent class membership.

Results

Three comparable latent classes were identified across the three surveys: Moderate hygiene compliance (Class 1), High hygiene compliance (Class 2), and Vigilance (Class 3). The prevalence of Class 1 was 48–52 % across the three surveys while Class 3 prevalence increased significantly from 13 % in the Dec-2013 survey to 20 % in the Feb-2014 survey. Compared with Class 1, Class 3 were more likely to be female, older, better educated, married, perceive higher susceptibility to H7N9, attribute greater severity to H7N9, report higher current worry, and anticipated worry about H7N9 infection.

Conclusion

The three classes reflect different levels of adoption of protection and thereby may have different levels of vulnerability toward contracting H7N9 infection. It appears that as the epidemic intensifies, Class 2 (Good hygiene compliance) members are likely to transfer to Class 3 (Vigilance) while Class 1 (Moderate hygiene compliance) could be unchanged. The young, mostly single males and those with lower educational achievement represent a group for whom public health messages need to be targeted.

Socioeconomic disparities in preterm birth and birth weight in a non-Western developed setting: evidence from Hong Kong's 'Children of 1997' birth cohort

BACKGROUND

Preterm birth (PTB), low birth weight and small-for-gestational age (SGA) are associated with lower socioeconomic position (SEP) in developed Western settings, but it is unclear if such disparities persist to the same extent elsewhere, and whether associations differ by measure of SEP used. Here, we assessed the association of SEP with PTB, birth weight and SGA in the recently developed non-Western setting of Hong Kong where few women smoke or use alcohol.

METHODS

We used multivariable logistic and linear regression to assess the associations of parental and neighbourhood SEP with PTB, birth weight and SGA among 8173 singleton births from the Hong Kong population-representative 'Children of 1997' birth cohort.

RESULTS

The only measure of SEP associated with PTB was type of housing adjusted for maternal age (p for trend 0.046). Highest paternal education had a small positive association with birth weight adjusted for gestational age (21 g, 95% CI 0.2 to 43 g for ≥grade 12 compared with ≤grade 9), as did residing in private compared with public housing (21 g, 95% CI 3 to 39 g). However, these associations did not persist after adjusting for mother's age. Lower neighbourhood Gini coefficient adjusted for mother's age was associated with a lower risk of SGA (OR 0.78, 95% CI 0.63 to 0.98). None of these associations remained after adjusting for multiple comparisons.

CONCLUSIONS

PTB, birth weight and SGA may be less clearly socially patterned in Hong Kong than other developed settings, highlighting the need for setting-specific interventions to prevent adverse birth outcomes.

Effect of Live Poultry Market Closure on Avian Influenza A(H7N9) Virus Activity in Guangzhou, China, 2014

Temporary closure and disinfection can rapidly reduce levels of infectious virus in these settings.

We assessed the effect of closing live poultry markets in China on influenza A(H7N9) virus detection and viability. Intensive sampling was carried out before, during, and after a 2-week citywide market closure; the markets were cleaned and disinfected at the beginning of the closure period. Swab samples were collected at different sites within the markets and tested for H7N9 by real-time reverse transcription PCR and culture. During the closure, H7N9 viral RNA detection and isolation rates in retail markets decreased by 79% (95% CI 64%–88%) and 92% (95% CI 58%–98%), respectively. However, viable H7N9 virus could be cultured from wastewater samples collected up to 2 days after the market closure began. Our findings indicates that poultry workers and the general population are constantly exposed to H7N9 virus at these markets and that market closure and disinfection rapidly reduces the amount of viable virus.

Individual Correlates of Infectivity of Influenza A Virus Infections in Households

BACKGROUND

Identifying individual correlates of infectivity of influenza virus is important for disease control and prevention. Viral shedding is used as a proxy measure of infectivity in many studies. However, the evidence for this is limited.

METHODS

In a detailed study of influenza virus transmission within households in 2008-12, we recruited index cases with confirmed influenza infection from outpatient clinics, and followed up their household contacts for 7-10 days to identify secondary infections. We used individual-based hazard models to characterize the relationship between individual viral shedding and individual infectivity.

RESULTS

We analyzed 386 households with 1147 household contacts. Index cases were separated into 3 groups according to their estimated level of viral shedding at symptom onset. We did not find a statistically significant association of virus shedding with transmission. Index cases in medium and higher viral shedding groups were estimated to have 21% (95% CI: -29%, 113%) and 44% (CI: -16%, 167%) higher infectivity, compared with those in the lower viral shedding group.

CONCLUSIONS

Individual viral load measured by RT-PCR in the nose and throat was at most weakly correlated with individual infectivity in households. Other correlates of infectivity should be examined in future studies.

Brief Report: Incubation Period Duration and Severity of Clinical Disease Following Severe Acute Respiratory Syndrome Coronavirus Infection

BACKGROUND

Few previous studies have investigated the association between the severity of an infectious disease and the length of incubation period.

METHODS

We estimated the association between the length of the incubation period and the severity of infection with the severe acute respiratory syndrome coronavirus, using data from the epidemic in 2003 in Hong Kong.

RESULTS

We estimated the incubation period of severe acute respiratory syndrome based on a subset of patients with available data on exposure periods and a separate subset of patients in a putative common source outbreak, and we found associations between shorter incubation period and greater severity in both groups after adjusting for potential confounders.

CONCLUSIONS

Our findings suggest that patients with a shorter incubation period went on to have more severe disease. Further studies are needed to investigate potential biological mechanisms for this association.

Toward a Common Secure Future: Four Global Commissions in the Wake of Ebola

Lawrence Gostin and colleagues offer a set of priorities for global health preparedness and response for future infectious disease threats.

Correction: Routine Pediatric Enterovirus 71 Vaccination in China: a Cost-Effectiveness Analysis

[This corrects the article DOI: 10.1371/journal.pmed.1001975.].

Human exposure to live poultry and psychological and behavioral responses to influenza A(H7N9), China

Exposure was common in urban and rural areas and remains a potential risk factor for human infection.

To investigate human exposure to live poultry and changes in risk perception and behavior after the April 2013 influenza A(H7N9) outbreak in China, we surveyed 2,504 urban residents in 5 cities and 1,227 rural residents in 4 provinces and found that perceived risk for influenza A(H7N9) was low. The highest rate of exposure to live poultry was reported in Guangzhou, where 47% of those surveyed reported visiting a live poultry market >1 times in the previous year. Most (77%) urban respondents reported that they visited live markets less often after influenza A(H7N9) cases were first identified in China in March 2013, but only 30% supported permanent closure of the markets to control the epidemic. In rural areas, 48% of respondents reported that they raised backyard poultry. Exposure to live commercial and private poultry is common in urban and rural China and remains a potential risk factor for human infection with novel influenza viruses.