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Population attributable estimates and Risk factors for Hepatitis.

Author(s) Bilal Ahmed1, Tooba Ali2, Huma Qureshi3, Saeed Hamid 4
Affiliation(s) 1Department of Medicine , The Aga Khan Univesity , Karachi, Pakistan, 2Medicine , The Aga Khan University , Karachi, Pakistan, 3PMRC, Pakistan Medical and Research Council, Karachi, Pakistan, 4Medicine, The Aga Khan university , Karachi, Pakistan.
Country - ies of focus Pakistan
Relevant to the conference tracks Infectious Diseases
Summary Estimation of population attributable risks indicates the potential for prevention of hepatitis if the exposure to certain modifiable factors could be eliminated.
We estimated the population attributable risks and performed systemetic review of various risk factors for transmission of HBV and HCV ( in 2012) using data from a large nationally representative survey conducted in 2007 across Pakistan.
A substantial number of HBV and HCV infections in Pakistan and other South Asian countries can be prevented by key interventions targeted towards a few selected and modifiable risk factors.
Background Viral hepatitis is a major public health disease worldwide with serious morbidity and mortality. South Asia lies among endemic regions where about 70 to 90% of the population become HBV-exposed before the age of 40, with 8 to 20% of people going on to become HBV carriers.
Objectives Data from Pakistan provides an important opportunity to better analyze and understand the most important attributable risks associated with specific factors for transmission of these infections in order to inform effective prevention and control policies. Previous analyses have estimated the odds ratios of various factors associated with HBV and HCV infection in our population, however these estimates do not provide information about the potential impact on disease occurrence that could be expected by eliminating these risk factors. In the present study we have tried to calculate population attributable risk (PAR) that can provide information as a quantitative assessment of the potential reduction in disease prevalence if the exposure in question were eliminated from our population. This study can potentially be generalized as applicable to other South Asian countries with similar background risks. The present analysis constitutes the first attempt at a comprehensive study of the population impact of risk factors for hepatitis B and C.
Methodology From July 2007 to May 2008, a nationally represented cross sectional survey was conducted in all urban and rural areas of the four provinces of Pakistan. The target population was the local residents of all territories of the country. The sampling frame was designed by the Federal Bureau of Statistics so as to be representative of the country’s population. A multistage sampling strategy was used by classifying cities and towns into well-defined enumeration blocks that constituted the primary sampling units (PSU). Taking population size in each province, and keeping in mind rural/urban proportions, 350 PSUs with 20 houses in each PSU were pre selected. House to house investigation was completed by trained staff based on the sampled household list. Information on demography, ethnicity, socioeconomic status, education, employment and marital status was collected by using standardized questionnaires. Altogether 7000 households were sampled and approximately 47000 individuals were tested for hepatitis B surface antigen (HBsAg) and anti-HCV antibody using rapid tests based on enzyme-linked immunosorbent assays (ELISA). For HBeAg testing a chemiluminescence method was used (CIMA), approved by FDA for field testing for HBV and HCV.
The risk factors under study were frequency of therapeutic intramuscular injections in the past one year, types of syringes used and categorized as new disposable or reused syringes, practice of shaving among males at home or by a barber, tattooing or acupuncture within the last five years, ear or nose piercing among females within the last five years and sharing tooth brush, miswak (herbal twig for dental hygiene) or sharing smoking utensils (hokas, bidi).In the present analysis we calculated the population attributable risk associated with modifiable factors for HBV and HCV in our population. The population attributable risk is defined as the proportion of hepatitis cases that can be related to a given risk factor (or set of risk factors) and is useful in assessing its impact at the population level. Estimation of population attributable risk was obtained by using an approach based on unadjusted logistic regression.
Additionally, a systematic review for the prevalence of modifiable risk factors associated with HBV and HCV from the South Asian region was performed to study the disease dynamics in this region, which could help in designing a holistic intervention strategy for disease prevention.
Results Analysis showed that the odds ratio of HBV infection among those with greater than 10 therapeutic injections in the past one year were 4.5 times higher compared to those who had received no injections, yielding a population attributable risk of 3.5%. Likewise, practice of reuse of syringes was 3.7 times higher compared to those who had received no injections giving a PAR of 2.7%. Another modifiable risk factor i.e. practice of shaving at barbers was 4.1 times higher compared to shaving at home with a PAR of 2.1%. Similarly, the odds of sharing of smoking devices (cigarettes, hokka, bidi) were 2.5 times more associated with the outcome, giving the highest population attributable risk of 4.4%.The odds of HCV infection among those with greater than 10 therapeutic injections in the past one year were 8.1 times higher compared to those who had received no injections, yielding a population attributable risk of 11.3%. Similarly, the practice of reuse of syringes was 6.8 times more associated with the occurrence of HCV giving a PAR of 6.2%. The practice of sharing of smoking (cigarettes, hokas, bidi) was 11.5 times more associated with HCV with a PAR of 5.1%. Odds of HCV among those reporting tattooing are 8.3 times, yielding a population attributable risk of 3.5%.
In the overall study population 34 % of hepatitis cases could be attributed to at least one of the seven well established risk factors. Therefore a substantial number of cases of hepatitis B and C can be prevented by eliminating these risk factors
Findings of systematic review:
We identified approximately 30 full text articles from the south Asian region that focused on the risk factors for transmission of viral hepatitis (see annexure). HBV and HCV epidemiology shows a high variability across the South Asian region, however both viruses bear common risk factors for transmissibility in this geographical region. Majority of these factors are related to health delivery and life style practices and are completely modifiable. Reuse of needles, shaving practices and body piercing are significantly prominent in the region.
We recognize that there are certain limitations to this study. One of the major limitations in the primary study was not using multistage cluster sampling and appropriate sampling weight at the design phase of the study, which limits our external generalizability. Besides this, causality is important for the interpretation of the PAR.
Conclusion A substantial number of HBV and HCV infections in Pakistan and other South Asian countries can be prevented by key interventions targeted towards a few selected and modifiable risk factors. Hence policies specifically targeted at key risk factors for HBV and HCV, such as safe and rationale use of injections prescribed by trained healthcare providers, are urgently needed for countries like Pakistan.This study indicates that about one-third of the hepatitis B and hepatitis C cases in the Pakistani population could be prevented by interventions in a few selected and modifiable risk factors: decreasing the frequency of therapeutic intramuscular injections, stopping the practice of re-used syringes and needles, avoiding shaving at barbers, prohibiting sharing of tooth brushes, razors and smoking utensils like hukka, avoiding tattooing and prohibiting the use of non-sterilized tools for ear /nose piercing.Our results show that about 33% of hepatitis B and C are attributed to the factors identified earlier and at least 67% are still unexplained and might be associated with other factors like blood transfusions, hemodialysis, previous surgery etc, for which the data were not collected in our primary study.The findings of our study have huge implications from public health perspective. Pakistan’s national hepatitis control program is mainly working on providing vaccination against HBV to the newborn and high risk groups, providing treatment for chronic HBV and HCV infection, and raising public awareness about these viruses. Improved surveillance to monitor incidence and prevalence of viral hepatitis, along with creating awareness and utilising low cost interventions among the general public and high risk individuals by media campaigns would help in reducing the burden of hepatitis. Strict policies and regulations for the prohibition of reused syringes and use of unsterilised tools, together with some life style changes, will help curtail the burden of the disease. Strengthening hepatitis B vaccination program is an effective step toward preventing transmission.

Predictors of Unintentional Poisoning among Children under 5 years of age in Karachi. A Matched Case Control study.

Author(s) Bilal Ahmed1, Zafar Fatmi2, Rehana Siddiqui3.
Affiliation(s) 1Department of Medicine , The Aga Khan Univesity , Karachi, Pakistan, 2Community Health Sciences, The Aga Khan University , Karachi, Pakistan, 3Community Health Sciences, The Aga Khan University , Karachi, Pakistan.
Country - ies of focus Pakistan
Relevant to the conference tracks Chronic Diseases
Summary Poisoning is one of the main causes of unintentional injury among children. It is the fourth leading cause of morbidity and mortality after road traffic accident, burns and drowning. Majority of these poisoning occur among preschool children under 5 years of age. There is a scarcity of evidence based analytical literature in the area of unintentional injuries, therefore there is need to identify the specific factors in our population in order to provide follow up action that reduces morbidity and mortality in young children and improves the handling of such emergencies by parents and health care workers.
Background Global estimates for childhood unintentional poisoning are not available and most of the existing information is from developed countries. There were an estimated 86,194 child poisoning incidents treated in United States hospital emergency departments in 2004, amounting to 429.4 poisoning per 100,000 children. Since morbidity is comparatively more associated with unintentional poisoning than mortality, non fatal incidents occur more among children of 1-4 years of age. Previous studies identified kerosene, petrol, medicines, insecticides, and household cleaning products as major hazards for poisoning incidents in children less than 5 years. Kerosene oil poisoning is commonly reported from developing countries. For cooking and lighting the main fuel use is paraffin (kerosene) and petrol for power generators, which is often stored under the beds in beverage or other empty containers. Unintentional ingestion of medicines both over the counter and prescription drugs, by young children and toddlers has been often reported. Similarly, household chemicals like bleach, toilet cleaners are also common substances involved in unintentional poisoning. Pakistan is a developing and low income country and, with more than 24 million children under 5 years of age, is highly vulnerable to such incidents.
Objectives There are few descriptive surveys available from Pakistan on unintentional childhood poisoning. However, there is a scarcity of analytical based epidemiological studies that has focused on factors within households that are associated with poisoning among young children. Epidemiological studies investigating the etiology of unintentional poisoning in children have been reported from the developed world or Malaysia and Greece.
As mentioned earlier, the majority of poisoning incidences occur inside home, however factors associated with household environment, behavioral issues of children and storage practices of caregivers have not been studied in our setting before. Monitoring of acute poisoning is important for health authorities because they can identify major factors involved in a particular population to prevent them. There is a scarcity of evidence based analytical literature in this area of unintentional injuries, therefore there is need to identify the specific factors in our population in order to enact follow up action that reduces morbidity and mortality in young children and improves handling of such emergencies by parents and health care workers. Moreover, it would help in designing appropriate strategies and interventions to create awareness in general population to reduce the burden of childhood poisoning.The key objectives are to determine the factors associated with poisoning among children under-5 years of age reporting to Emergency rooms of tertiary care hospitals in Karachi.
Methodology This study was conducted in the ERs of three large tertiary care hospitals in Karachi: the Aga Khan University Hospital (AKUH), the Civil Hospital Karachi (CHK), and the National Institute of Child Health (NICH). AKUH, a private hospital, caters
for 12 000 paediatric patients annually, whereas CHK and NICH are public hospitals, and receive approximately 150 paediatric patients in the ER daily. These hospitals provide services for the upper, middle and lower socioeconomic classes of the Karachi population. The study data were collected from August 2008 to March 2009. The investigation was a matched case control study. All consecutive poisoning cases were enrolled in the study, including gravely ill children or those who died either in the ER or before reaching the hospitals during the study period.The cases were defined as being children under 5 years of age with oral ingestion of any noxious substances. They were recruited into the study after a definite diagnosis of accidental intake of poisoning was made by the attending physician of the respective hospitals. The noxious agents considered for poisoning in this study were any substance that had the
potential for toxic effects and included medicines, insecticides, pesticides, petroleum products, household chemicals, and cosmetics. Children admitted for food poisoning, adverse drug reactions, and poisoning with animal venom were excluded. Controls were selected from the ER of the same hospitals and comprised of children with complaints other than poisoning. Controls were matched for age (66 months) and sex, as these were the known confounders. Three control children per case visiting the ER of the same hospital within 48 h of case identification were enrolled for the study. Children with symptoms of chronic illness such as known cases of cardiac disease, renal failure, chronic pulmonary disease, cancer patients, and road traffic accidents were excluded from the study sample. Children brought from nearby areas outside Karachi were not included in the study. Caregivers were interviewed using a structured questionnaire. Information on the sociodemographic characteristics of the child and caregiver, and the storage practices for medicines and chemicals in their household, were obtained.
Sample size: a total number of 120 cases and 360 controls were required to achieve the objectives of the study. Multivariable conditional logistic regression analysis was done and adjusted matched odds ratios (mORs) were calculated.
Results The data included 120 cases and 360 matched controls. Incidental uptake of medicines was the most common type of poisoning, followed by kerosene oil ingestion. Similarly, the majority of the incidents of poisoning occurred in the bedroom followed by the drawing/dining room, courtyard and kitchen. Among all the subjects enrolled during the study period, only one cased who had ingested medicine (warfarin) died. The majority of poisoning incidents occurred among children 1-2 years of age. Among the cases medicinal users at home, history of previous poisoning incident, and child behaviour reported as aggressive were more prevalent than among controls. Similarly, the proportion of parents living apart and living in a nuclear family system was more in cases than controls. The storage practices of medicines and chemicals showed that the proportion of unsafe storage of chemicals that is not at a height >2 m is greater among cases than controls (30.8% vs 16.7%). Similarly, more households of cases (80%) stored unlocked chemicals compared to controls (56.1%). Among the cases the safe storage of medicine at a height >2 m was 64.2% compared with 75.3% for the controls. Only 8.3% of the caregivers of cases reported that they kept medicines locked, compared to 23.6% of the controls. However, when these variables were combined to make a composite variable it showed that 14.2% of the caregivers of cases reported storing both chemicals and medicine unsafely, compared to 5.8% of controls. Adjusted analysis shows that, accessibility to hazardous chemicals and medicines was significantly associated with poisoning. Unsafe storage of either chemicals or medicines occurred 1.5 times more in cases compared to controls. Similarly, unsafe storage of both chemicals and medicines occurred 5.6 times more in cases compared to controls (mORadj 5.6, 95% 95% CI 1.9 to 16.7). Storage of kerosene and petroleum in soft drink bottles occurred 3.8 times more in cases compared to controls (mORadj=3.8, 95% CI 2.0 to 7.3). Cases were 8.2 times more likely to be aggressive compared to controls (mORadj=8.2, 95% CI 4.2 to 16.1). Similarly, the reporting of a previous poisoning incidence was 8.6 times more in cases compared to controls (mORadj=8.6, 95% CI 1.7 to 43.5). The low level of mother’s education was strongly associated with poisoning in children.
Conclusion In conclusion, we found that accessibility of hazardous chemicals and medicines due to unsafe storage, reported child behavior as aggressiveness, history of previous poisoning, low maternal education, storing of kerosene and petroleum in soft drink bottles, and low socio economic status were associated with increased risk of unintentional poisoning among children under-5 years of age living in Karachi. Some of these factors, particularly storage practices, are potentially modifiable and efforts to reduce the prevalence of unsafe storage could have the benefit of reducing the incidence of unintentional poisoning in this population. To curtail the number of childhood poisoning incidents understanding its related preceding factors in particular settings are necessary. Future directions in the field of childhood poisoning involves a number of strategies including the incorporation of better-tested and more refined educational, legislative, and environmental intervention strategies. As mentioned earlier, there is a scarcity of literature in the area of childhood injuries. The large community base studies, emergency room surveillance system for overall unintentional childhood injuries including poisoning, and population base follow-up studies helps to determine the predictors. Studies of risk factors have to be conducted and analyzed with due regard to possible confounding variables and interaction between factors. Similarly, cost effective and sustainable intervention needs to be launched, to see if it decreases the burden. Qualitative focus group discussions with parents of young children about real and perceived barriers to calling the local poison information center, resources for poison prevention messages, and ideas about public awareness campaigns should also be done.
Intervention and longitudinal studies can further provide the necessary evidence in understanding the behavioral issues of children, parents and other care givers that could lead to unintentional ingestion of harmful substances to further establish temporality and causal association.