Ethics guidelines for environmental epidemiologists: 2023 revision.

Recognition of the importance to environmental epidemiology of ethical and philosophical deliberation led, in 1996, to the establishment of Ethics Guidelines for the profession. In 1999, these guidelines were adopted by the International Society for Environmental Epidemiology. The guidelines were revised in 2012 and again in 2023 to ensure continued relevance to the major issues facing the field. Comprising normative standards of professional conduct, the guidelines are structured into four subsections: (1) obligations to individuals and communities who participate in research; (2) obligations to society; (3) obligations regarding funders/sponsors and employers; and (4) obligations to colleagues. Through the 2023 revision of the Ethics Guidelines, the International Society for Environmental Epidemiology seeks to ensure the highest possible standards of transparency and accountability for the ethical conduct of environmental epidemiologists engaged in research and public health practice.

Effectiveness of educational interventions on hypertensive patients' self-management behaviours: an umbrella review protocol.

BACKGROUND: Although different educational interventions have been widely used to manage and treat hypertension, alone or in combination with other interventions, there is a significant variation in their claimed effectiveness. REVIEW QUESTION/OBJECTIVE: The objective of this umbrella review is to determine the effectiveness of educational interventions, alone or in combination with other interventions, for improving blood pressure control and self-management practices among hypertensive patients. The review question is: Do educational interventions, alone or in combination with other interventions, improve self-management practices among patients with hypertension? METHODS: We will conduct a review of systematic reviews involving studies that implemented educational interventions, alone or in combination with other interventions, designed to change self-care practices among hypertensive patients who are 18 years and above, regardless of their sex and ethnicity. Following the guidelines set forth in the Preferred Reporting Items for Systematic Review and Meta-Analysis statement, a comprehensive literature search will be conducted from September to December 2023 on six electronic databases: MEDLINE, Embase, PsycINFO, CINAHL, Web of Science Core Collection and Google Scholar. Search terms will be developed using database-specific indexed terms and text words derived from the review aim. We will present the effects of the educational interventions, alone or in combination with other interventions, on hypertension self-management practices. We will report the outcome data with 95% CIs for each study. Relative risk, mean differences or ORs will be used, depending on the measuring indices in each study. ETHICS AND DISSEMINATION: Ethical approval is not required as this study will use aggregated data from previously published systematic reviews. However, we have registered the protocol in PROSPERO. We confirm that all methods will be performed following the guidelines of the Declaration of Helsinki. The findings from this study will be disseminated through presentations at academic conferences and publication in peer-reviewed international journals. PROSPERO REGISTRATION NUMBER: CRD42022375581.

The effect of geographical variation in income measures on measles-mumps-rubella uptake and coverage in England; a protocol for an ecological study.

Measles is a vaccine-preventable disease whose vaccine was introduced in England in 1988, however, Measles outbreaks have still been occurring in the country. Consequently, the World Health Organization (WHO) removed the elimination status of Measles in 2019 from England and the whole United Kingdom. Noticeably, MMR vaccination coverage in England is below the recommended threshold with geographical variations across local authorities (LA). The research into the effect of income disparities on MMR vaccine coverage was insufficiently examined. Therefore, an ecological study will be conducted aiming at determining whether there is a relationship between income deprivation measures and MMR vaccine coverage in upper-tier local authorities in England. This study will be using 2019 publicly available vaccination data for children who were eligible for the MMR vaccine by their second and fifth birthday in 2018/2019. The effect of spatial clustering of income level on vaccination coverage will also be assessed. Vaccination coverage data will be obtained from "Cover of Vaccination Evaluated Rapidly (COVER)". Income deprivation score, Deprivation gap, and Income Deprivation Affecting Children Index will be obtained from Office for National Statistics and Moran's Index will be generated using RStudio. Rural/urban LA classification and mothers' education will be included as possible confounding factors. Additionally, the live births rate per mothers' age group will be included as a proxy for the mothers' age variation in different LA. Multiple linear regression will be used after testing the relevant assumptions, using SPSS software. Moran's I together with income deprivation score will be analysed through regression and mediation analysis. This study will help in determining whether income level is a determinant of MMR vaccination uptake and coverage in LA in England which would help policymakers in designing targeted campaigns, thus preventing measles outbreaks in the future.

Hormone Replacement Therapy and Risk of Severe Asthma Exacerbation in Perimenopausal and Postmenopausal Women: 17-Year National Cohort Study.

BACKGROUND: The impact of hormone replacement therapy (HRT) on clinical outcomes in menopausal women is uncertain. OBJECTIVE: To investigate the association between use of HRT and severe asthma exacerbation in perimenopausal and postmenopausal women with asthma. METHODS: We used the Optimum Patient Care Research Database, a population-based longitudinal primary care database in the United Kingdom, to construct a 17-year (January 1, 2000, to December 31, 2016) cohort of perimenopausal and postmenopausal (46-70 years, N = 31,656) women. We defined use of HRT, its subtypes, and duration of HRT use. Severe asthma exacerbation was defined as an asthma-related hospitalization, emergency department visits due to asthma, and/or prescription of oral corticosteroids. Analyses were undertaken using multilevel mixed-effects Poisson regression. RESULTS: At baseline, 22% of women were using any HRT, 11% combined HRT, and 11% estrogen-only HRT. Previous, but not current, use of any (incidence rate ratio [IRR]: 1.24, 95% confidence interval [CI]: 1.22-1.26), combined (IRR: 1.28, 95% CI: 1.25-1.31), and estrogen-only HRT (IRR: 1.18, 95% CI: 1.14-1.21), and longer duration (1-2 years: IRR: 1.16, 95% CI: 1.13-1.19; 3-4 years: IRR: 1.43, 95% CI: 1.38-1.48; 5+ years: IRR: 1.32, 95% CI: 1.28-1.36) of HRT use were associated with increased risk of severe asthma exacerbation compared with nonuse. The risk estimates were greater among lean women (body mass index [BMI] <25 kg/m2) than among heavier women (BMI 25-29.9 kg/m2 and ≥30 kg/m2) and higher among smokers than nonsmokers. CONCLUSION: Use of HRT and subtypes, particularly previous, but not current, use and use for more than 2 years, is associated with an increased risk of severe asthma exacerbation in perimenopausal/postmenopausal women with established asthma. Lean women and smokers are at greater risk than heavier women and nonsmokers, respectively.

Hormone replacement therapy and asthma onset in menopausal women: National cohort study.

BACKGROUND: There is uncertainty about the role of hormonal replacement therapy (HRT) in the development of asthma. OBJECTIVE: We investigated whether use of HRT and duration of use was associated with risk of development of asthma in perimenopausal and postmenopausal women. METHODS: We constructed a 17-year (from January 1, 2000, to December 31, 2016) open cohort of 353,173 women (aged 46-70 years) from the Optimum Patient Care Database, a longitudinal primary care database from across the United Kingdom. HRT use, subtypes, and duration of use; confounding variables; and asthma onset were defined by using the Read Clinical Classification System. We fitted multilevel Cox regression models to estimate hazard ratios (HRs) with 95% CIs. RESULTS: During the 17-year follow-up (1,340,423 person years), 7,614 new asthma cases occurred, giving an incidence rate of 5.7 (95% CI = 5.5-5.8) per 1,000 person years. Compared with nonuse of HRT, previous use of any (HR = 0.83; 95% CI = 0.76-0.88), estrogen-only (HR = 0.89; 95% CI = 0.84-0.95), or combined estrogen and progestogen (HR = 0.82; 95% CI = 0.76-0.88) HRT was associated with a reduced risk of asthma onset. This was also the case with current use of any (HR = 0.79; 95% CI = 0.74-0.85), estrogen-only (HR = 0.80; 95% CI = 0.73-0.87), and combined estrogen and progestogen (HR = 0.78; 95% CI = 0.70-0.87) HRT. Longer duration of HRT use (1-2 years [HR = 0.93; 95% CI = 0.87-0.99]; 3-4 years [HR = 0.77; 95% CI = 0.70-0.84]; and ≥5 years [HR = 0.71; 95% CI = 0.64-0.78]) was associated with a dose-response reduced risk of asthma onset. CONCLUSION: We found that HRT was associated with a reduced risk of development of late onset asthma in menopausal women. Further cohort studies are needed to confirm these findings.

Hormonal contraception and the risk of severe asthma exacerbation: 17-year population-based cohort study.

BACKGROUND: Longitudinal studies investigating impact of exogenous sex steroids on clinical outcomes of asthma in women are lacking. We investigated the association between use of hormonal contraceptives and risk of severe asthma exacerbation in reproductive-age women with asthma. METHODS: We used the Optimum Patient Care Research Database, a population-based, longitudinal, anonymised primary care database in the UK, to construct a 17-year (1 January 2000-31 December 2016) retrospective cohort of reproductive-age (16-45 years, n=83 084) women with asthma. Using Read codes, we defined use, subtypes and duration of use of hormonal contraceptives. Severe asthma exacerbation was defined according to recommendations of the European Respiratory Society/American Thoracic Society as asthma-related hospitalisation, accident and emergency department visits due to asthma and/or oral corticosteroid prescriptions. Analyses were done using multilevel mixed-effects Poisson regression with QR decomposition. RESULTS: The 17-year follow-up resulted in 456 803 person-years of follow-up time. At baseline, 34% of women were using any hormonal contraceptives, 25% combined (oestrogen/progestogen) and 9% progestogen-only contraceptives. Previous (incidence rate ratio (IRR) 0.94, 95% CI 0.92 to 0.97) and current (IRR 0.96, 95% CI 0.94 to 0.98) use of any, previous (IRR 0.92, 95% CI 0.87 to 0.97) and current use of combined (IRR 0.93, 95% CI 0.91 to 0.96) and longer duration of use (3-4 years: IRR 0.94, 95% CI 0.92 to 0.97; 5+ years: IRR 0.91, 95% CI 0.89 to 0.93) of hormonal contraceptives, but not progestogen-only contraceptives, were associated with reduced risk of severe asthma exacerbation compared with non-use. CONCLUSIONS: Use of hormonal contraceptives may reduce the risk of severe asthma exacerbation in reproductive-age women. Mechanistic studies investigating the biological basis for the influence of hormonal contraceptives on clinical outcomes of asthma in women are required. PROTOCOL REGISTRATION NUMBER: European Union electronic Register of Post-Authorisation Studies (EUPAS22967).

Hormonal contraceptives and onset of asthma in reproductive-age women: Population-based cohort study.

BACKGROUND: Despite well-described sex differences in asthma incidence, there remains uncertainty about the role of female sex hormones in the development of asthma. OBJECTIVE: We sought to investigate whether hormonal contraceptive use, its subtypes, and duration of use were associated with new-onset asthma in reproductive-age women. METHODS: Using the Optimum Patient Care Research Database, a UK national primary care database, we constructed an open cohort of 16- to 45-year-old women (N = 564,896) followed for up to 17 years (ie, January 1, 2000, to December 31, 2016). We fitted multilevel Cox regression models to analyze the data. RESULTS: At baseline, 26% of women were using any hormonal contraceptives. During follow-up (3,597,146 person-years), 25,288 women developed asthma, an incidence rate of 7.0 (95% CI, 6.9-7.1) per 1000 person-years. Compared with nonuse, previous use of any hormonal contraceptives (hazard ratio [HR], 0.70; 95% CI, 0.68-0.72), combined (HR, 0.70; 95% CI, 0.68-0.72), and progestogen-only therapy (HR, 0.70; 95% CI, 0.67-0.74) was associated with reduced risk of new-onset asthma. For current use, the estimates were as follows: any (HR, 0.63; 95% CI, 0.61-0.65), combined (HR, 0.65; 95% CI, 0.62-0.67), and progestogen-only therapy (HR, 0.59; 95% CI, 0.56-0.62). Longer duration of use (1-2 years: HR, 0.83; 95% CI, 0.81-0.86; 3-4 years: HR, 0.64; 95% CI, 0.61-0.67; 5+ years: HR, 0.46; 95% CI, 0.44-0.49) was associated with a lower risk of asthma onset than nonuse. CONCLUSIONS: Hormonal contraceptive use was associated with reduced risk of new-onset asthma in women of reproductive age. Mechanistic investigations to uncover the biological processes for these observations are required. Clinical trials investigating the safety and effectiveness of hormonal contraceptives for primary prevention of asthma will be helpful to confirm these results.

Exogenous sex steroid hormones and asthma in females: protocol for a population-based retrospective cohort study using a UK primary care database.

INTRODUCTION: Female sex steroid hormones have been implicated in sex-related differences in the development and clinical outcomes of asthma. The role of exogenous sex steroids, however, remains unclear. Our recent systematic review highlighted the lack of high-quality population-based studies investigating this subject. We aim to investigate whether the use of hormonal contraception and hormone replacement therapy (HRT), subtypes and route of administration are associated with asthma onset and clinical outcomes in reproductive age and perimenopausal/postmenopausal females. METHODS AND ANALYSIS: Using the Optimum Patient Care Research Database (OPCRD), a national primary care database in the UK, we will construct a retrospective longitudinal cohort of reproductive age (16-45 years) and perimenopausal/postmenopausal (46-70 years) females. We will estimate the risk of new-onset asthma using Cox regression and multilevel modelling for repeated asthma outcomes, such as asthma attacks. We will adjust for confounding factors in all analyses. We will evaluate interactions between the use of exogenous sex hormones and body mass index and smoking by calculating the relative excess risk due to interaction and the attributable proportion due to interaction. With 90% power, we need 23 700 reproductive age females to detect a 20% reduction (risk ratio 0.8) in asthma attacks for use of any hormonal contraception and 6000 perimenopausal/postmenopausal females to detect a 40% (risk ratio 1.40) increased risk of asthma attacks for use of any HRT. ETHICS AND DISSEMINATION: We have obtained approval (ADEPT1317) from the Anonymised Data Ethics and Protocol Transparency Committee which grants project-specific ethics approvals for the use of OPCRD data. Optimum Patient Care has an existing NHS Health Research Authority ethics approval for the use of OPCRD data for research (15/EM/150). We will present our findings at national and international scientific meetings and publish the results in international peer-reviewed journals. TRIAL REGISTRATION NUMBER: EUPAS22967.

Improving predictive asthma algorithms with modelled environment data for Scotland: an observational cohort study protocol.

INTRODUCTION: Asthma has a considerable, but potentially, avoidable burden on many populations globally. Scotland has some of the poorest health outcomes from asthma. Although ambient pollution, weather changes and sociodemographic factors have been associated with asthma attacks, it remains unclear whether modelled environment data and geospatial information can improve population-based asthma predictive algorithms. We aim to create the afferent loop of a national learning health system for asthma in Scotland. We will investigate the associations between ambient pollution, meteorological, geospatial and sociodemographic factors and asthma attacks. METHODS AND ANALYSIS: We will develop and implement a secured data governance and linkage framework to incorporate primary care health data, modelled environment data, geospatial population and sociodemographic data. Data from 75 recruited primary care practices (n=500 000 patients) in Scotland will be used. Modelled environment data on key air pollutants at a horizontal resolution of 5 km×5 km at hourly time steps will be generated using the EMEP4UK atmospheric chemistry transport modelling system for the datazones of the primary care practices' populations. Scottish population census and education databases will be incorporated into the linkage framework for analysis. We will then undertake a longitudinal retrospective observational analysis. Asthma outcomes include asthma hospitalisations and oral steroid prescriptions. Using a nested case-control study design, associations between all covariates will be measured using conditional logistic regression to account for the matched design and to identify suitable predictors and potential candidate algorithms for an asthma learning health system in Scotland.Findings from this study will contribute to the development of predictive algorithms for asthma outcomes and be used to form the basis for our learning health system prototype. ETHICS AND DISSEMINATION: The study received National Health Service Research Ethics Committee approval (16/SS/0130) and also obtained permissions via the Public Benefit and Privacy Panel for Health and Social Care in Scotland to access, collate and use the following data sets: population and housing census for Scotland; Scottish education data via the Scottish Exchange of Data and primary care data from general practice Data Custodians. Analytic code will be made available in the open source GitHub website. The results of this study will be published in international peer reviewed journals.

Predicting probable Alzheimer's disease using linguistic deficits and biomarkers.

BACKGROUND: The manual diagnosis of neurodegenerative disorders such as Alzheimer's disease (AD) and related Dementias has been a challenge. Currently, these disorders are diagnosed using specific clinical diagnostic criteria and neuropsychological examinations. The use of several Machine Learning algorithms to build automated diagnostic models using low-level linguistic features resulting from verbal utterances could aid diagnosis of patients with probable AD from a large population. For this purpose, we developed different Machine Learning models on the DementiaBank language transcript clinical dataset, consisting of 99 patients with probable AD and 99 healthy controls. RESULTS: Our models learned several syntactic, lexical, and n-gram linguistic biomarkers to distinguish the probable AD group from the healthy group. In contrast to the healthy group, we found that the probable AD patients had significantly less usage of syntactic components and significantly higher usage of lexical components in their language. Also, we observed a significant difference in the use of n-grams as the healthy group were able to identify and make sense of more objects in their n-grams than the probable AD group. As such, our best diagnostic model significantly distinguished the probable AD group from the healthy elderly group with a better Area Under the Receiving Operating Characteristics Curve (AUC) using the Support Vector Machines (SVM). CONCLUSIONS: Experimental and statistical evaluations suggest that using ML algorithms for learning linguistic biomarkers from the verbal utterances of elderly individuals could help the clinical diagnosis of probable AD. We emphasise that the best ML model for predicting the disease group combines significant syntactic, lexical and top n-gram features. However, there is a need to train the diagnostic models on larger datasets, which could lead to a better AUC and clinical diagnosis of probable AD.

Prevalence of chronic obstructive pulmonary disease (COPD) in China in 1990 and 2010.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is set to become the third most frequent cause of death and also the third largest cause of global morbidity by 2020. In China, where the population is aging rapidly, COPD has become one of the leading causes of disability and a large economic burden. An epidemiological assessment of the COPD in China is required, with a focus on the number of cases living with disease, main determinants of the disease and time trends. METHODS: We systematically searched large Chinese bibliographic databases and English databases to identify spirometry-based epidemiological studies of the prevalence of COPD in China diagnosed according to GOLD criteria. We estimated age- and gender-specific prevalence of COPD using a multilevel mixed-effect logistic regression. We also presented the time trends of COPD between 1990 and 2010 by age, gender and setting (urban vs rural). FINDINGS: In 1990, the prevalence of COPD ranged from 0.49% (95% CI = 0.29-0.85) in <20 years group to 20.95% (95% CI = 14.04-27.04) in> = 80 years group, and the crude prevalence for China was 2.70% (95% CI = 1.86-3.51). In 2010, the prevalence in <20 years was 0.55% (95% CI = 0.37-1.04) and in> = 80 years was 22.89% (95% CI = 18.13-28.96), with the crude prevalence for China of 3.84% (95% CI = 3.30-4.77). The COPD prevalence in males was about two-fold higher than in females, and it increased with increasing age. Between 1990-2010, the total number of Chinese people living with COPD increased by 66.73%, from 30.90 million (95% CI = 21.28-40.02) in 1990 to 51.52 million (95% CI = 44.26-63.93) in 2010. This increase was most striking in middle age, and greater in females than in males from 30 years up to 64 years. Our estimates, which used an independent approach to acquiring data and development of analytical methods, and were based on a more complete data set, are remarkably similar to those produced recently by the GBD 2013 collaboration, differing by only about 5% in the estimated number of COPD cases in 1990 and by 1% in 2010. CONCLUSIONS: COPD is a highly prevalent disease in China and its importance is growing steadily. The number of people living with COPD has increased substantially between 1990 and 2010. COPD is more frequent in males and in rural areas. Optimised primary and secondary prevention and treatment is urgently needed to counter this growing trend. Improved epidemiological studies will be required to assist development of more effective strategies of prevention and treatment of COPD in China in the next decade and beyond.

Complementary feeding and the early origins of obesity risk: a study protocol.

INTRODUCTION: The rise in the prevalence of childhood obesity worldwide calls for an intervention earlier in the life cycle. Studies show that nutrition during early infancy may contribute to later obesity. Hence, this study is designed to determine if the variation in complementary feeding practices poses a risk for the development of obesity later in life. A mixed methods approach will be used in conducting this study. METHODS AND ANALYSIS: The target participants are infants born from January to June 2015 in the South East Asia Community Observatory (SEACO) platform. The SEACO is a Health and Demographic Surveillance System (HDSS) that is established in the District of Segamat in the state of Johor, Malaysia. For the quantitative strand, the sociodemographic data, feeding practices, anthropometry measurement and total nutrient intake will be assessed. The assessment will occur around the time complementary feeding is expected to start (7 Months) and again at 12 months. A 24-hour diet recall and a 2-day food diary will be used to assess the food intake. For the qualitative strand, selected mothers will be interviewed to explore their infant feeding practices and factors that influence their practices and food choices in detail. ETHICS AND DISSEMINATION: Ethical clearance for this study was sought through the Monash University Human Research and Ethics Committee (application number CF14/3850-2014002010). Subsequently, the findings of this study will be disseminated through peer-reviewed journals, national and international conferences.

Patient-reported outcome measures for allergy and asthma in children.

There is increasing recognition of the importance of patient's perceptions of disease and their assessments of heathcare processes. Patient-reported outcome measures (PROMs) are therefore now regarded as at least as important as the traditional objective measures of disease. For minors, parental and, except in the very young and severally cognitively impaired, the child's perspectives are important because they provide unique and complementary information. In this review, we summarize the evidence on PROMs for allergy and asthma for use in children. Overall, there are fewer PROMs available for use in children than in adults. We were able to identify some validated pediatric PROMs that have been developed for use in atopic eczema/dermatitis, food allergy, allergic rhinitis/rhinoconjunctivitis, and asthma. There is very limited evidence on deploying these instruments out with research settings. There is therefore a pressing need to report on the experiences of using PROMs for allergy and asthma in routine clinical care. In particular, there is a need to understand how acceptable these are to children/carers, whether they can be incorporated into routine clinical assessments and if they are responsive to changes in treatment made in routine clinical practice.

Building a recruitment database for asthma trials: a conceptual framework for the creation of the UK Database of Asthma Research Volunteers.

BACKGROUND: Randomised clinical trials are the 'gold standard' for evaluating the effectiveness of healthcare interventions. However, successful recruitment of participants remains a key challenge for many trialists. In this paper, we present a conceptual framework for creating a digital, population-based database for the recruitment of asthma patients into future asthma trials in the UK. Having set up the database, the goal is to then make it available to support investigators planning asthma clinical trials. METHODS: The UK Database of Asthma Research Volunteers will comprise a web-based front-end that interactively allows participant registration, and a back-end that houses the database containing participants' key relevant data. The database will be hosted and maintained at a secure server at the Asthma UK Centre for Applied Research based at The University of Edinburgh. Using a range of invitation strategies, key demographic and clinical data will be collected from those pre-consenting to consider participation in clinical trials. These data will, with consent, in due course, be linkable to other healthcare, social, economic, and genetic datasets. To use the database, asthma investigators will send their eligibility criteria for participant recruitment; eligible participants will then be informed about the new trial and asked if they wish to participate. A steering committee will oversee the running of the database, including approval of usage access. Novel communication strategies will be utilised to engage participants who are recruited into the database in order to avoid attrition as a result of waiting time to participation in a suitable trial, and to minimise the risk of their being approached when already enrolled in a trial. RESULTS: The value of this database will be whether it proves useful and usable to researchers in facilitating recruitment into clinical trials on asthma and whether patient privacy and data security are protected in meeting this aim. CONCLUSIONS: Successful recruitment is fundamental to the success of a clinical trial. The UK Database of Asthma Research Volunteers, the first of its kind in the context of asthma, presents a novel approach to overcoming recruitment barriers and will facilitate the catalysing of important clinical trials on asthma in the UK.

The rural bite in population pyramids: what are the implications for responsiveness of health systems in middle income countries?

BACKGROUND: Health services can only be responsive if they are designed to service the needs of the population at hand. In many low and middle income countries, the rate of urbanisation can leave the profile of the rural population quite different from the urban population. As a consequence, the kinds of services required for an urban population may be quite different from that required for a rural population. This is examined using data from the South East Asia Community Observatory in rural Malaysia and contrasting it with the national Malaysia population profile. METHODS: Census data were collected from 10,373 household and the sex and age of household members was recorded. Approximate Malaysian national age and sex profiles were downloaded from the US Census Bureau. The population pyramids, and the dependency and support ratios for the whole population and the SEACO sub-district population are compared. RESULTS: Based on the population profiles and the dependency ratios, the rural sub-district shows need for health services in the under 14 age group similar to that required nationally. In the older age group, however, the rural sub-district shows twice the need for services as the national data indicate. CONCLUSION: The health services needs of an older population will tend towards chronic conditions, rather than the typically acute conditions of childhood. The relatively greater number of older people in the rural population suggest a very different health services mix need. Community based population monitoring provides critical information to inform health systems.

Does one cigarette make an adolescent smoker, and is it influenced by age and age of smoking initiation? Evidence of association from the U.S. Youth Risk Behavior Surveillance System (2011).

OBJECTIVES: Evidence that age of smoking initiation represents a risk factor for regular smoking in adolescence is complicated by inconsistencies in the operational definition of smoking initiation and simultaneous inclusion of age as an explanatory variable. The aim of this study was to examine the relationship between age, age of smoking initiation and subsequent regular smoking. METHODS: A secondary analysis was conducted of the U.S. Youth Risk Behavior Survey 2011. A sex stratified multivariable logistic regression analysis was used to model the likelihood of regular smoking with age and age of smoking initiation as explanatory variables and race/ethnicity as a covariate. RESULTS: After controlling for race/ethnicity, age and age of smoking initiation were independently associated with regular smoking in males and females. Independent of age, a one year's decrease in the age of smoking initiation was associated with a 1.27 times increase in odds of regular smoking in females (95% CI: 1.192-1.348); and similar associations for males (OR: 1.28; 95% CI: 1.216-1.341). CONCLUSION: While the majority of high school students do not become regular smokers after initiating smoking, earlier initiation of smoking is associated with subsequent regular smoking irrespective of sex or race/ethnicity. These findings have potentially important implications for intervention targeting.