Epidemiology of adulthood drowning deaths in Bangladesh: Findings from a nationwide health and injury survey

Introduction

Drowning is the process of experiencing respiratory impairment from submersion or immersion in liquid, and the outcomes are classified as death, morbidity and no morbidity¹. Drowning is an important but neglected public health issue that affects children and youths in many societies worldwide^2,3. Following road traffic and injury sustained from falls, drowning is the 3^rd leading cause of injury death in the world, claiming 42 lives every hour and 372,000 lives a year, which is almost two thirds attributed to malnutrition and over half of malaria². Of all drowning deaths more than 90% occur in low and middle income countries where individuals are exposed to water during daily life^3–5. According to the WHO (2014), drowning contributes to 7% of all injury-related annual deaths worldwide⁶. South-East Asian countries are considered the most affected region with 2.49 million disability adjusted life years as a result of death and disability from drowning⁷.

Bangladesh is a low-lying, riverine country located in the subtropical region of South Asia and bordering with the Bay of Bengal. Its tropical monsoon climate is characterized by heavy rainfall and melting snow in the Himalayan territory, leading to large rivers, such as the Ganga, Brahmaputra and Meghna. The country has a landmass of 147,570 square kilometers and is one of the most densely inhabited countries in the world with a population of 160 million. Daily life in Bangladesh exposes people to water bodies, such as ponds, ditches, rivers, canals and the ocean, which are used for daily household needs, including agriculture, fishing and transportation. As a result, drowning effects all ages of the Bangladeshi population.

Most research on drowning conducted in Bangladesh has focused on childhood drowning^8–10. In Bangladesh, there is no established routine mortality registration system¹¹, which, combined with inadequacy of research¹², results in unknown drowning deaths among the adult population. To design an appropriate preventive measure for reducing adult drowning, it is important to determine the nationwide burden of drowning. Drowning mostly occurs among the rural populations⁸, so community-based household survey data is important. The objective of this study was to estimate fatal adult drowning in Bangladesh and its variation by sex, place of residence, and seasonality using a nationally representative survey.

Methods

Data for this study was extracted from Bangladesh Health and Injury Survey (BHIS), which was conducted during January and December 2003. The following methodology details how the survey data were collected.

Statistical analysis

Data related to drowning death were extracted from the main data set. As the recall period was over the last two years, only data from the last year was taken for analysis. Standard descriptive statistics were used to analyze the characteristics of adulthood drowning. Mean, standard deviation (SD), and proportion were used where appropriate. Drowning deaths were presented by gender, age, seasonality and place of residence. Age was categorized into seven groups (Figure 1). Rates were calculated with 95% confidence intervals (CI). Relative risk (RR) was calculated to compare the drowning risks in different age groups, place of residence, and gender using open EPI-Info software (http://www.openepi.com/Menu/OE_Menu.htm). The methodology has been described elsewhere^13–15.

Figure 1. Age wise annual incidence of fatal adult drowning in Bangladesh.

Results

Seasonality of drowning

The study findings revealed that drowning incidences were relatively low during the winter season (November to February). The incidence increased during March and September, which are considered as summer and monsoon season. The incidence peaked during March and April (Figure 2).

Figure 2. Seasonality of fatal drowning among adults in Bangladesh.

Discussion

In Bangladesh, natural and man-made water sources are commonly located in close proximity of households, especially in rural areas. People use these water sources for daily household needs, such as irrigation, fish farming, bathing, swimming, animal feeding and washing clothes. In addition to this, a large number of the population use water transport for regular travelling and goods carrying. As a result, regular exposure to water bodies is very high. Bangladeshi population are experiencing massive destructive natural disasters, such as floods and cyclones, frequently, which often cause a high number of unexpected drowning deaths (https://en.wikipedia.org/wiki/List_of_Bangladesh_tropical_cyclones). In this study, the main three causes of death due to drowning were bathing, working and travelling.

The survey findings revealed that the annual drowning fatality among adults aged 18 years and above is 5.85/100,000 individuals, which means annually about 8,195 fatal drownings take place among the adult population of Bangladesh. Of these 5,851 are male and 2,344 are female. Adult males were found to be 2.39 times higher at risk of drowning than females in this study. Our findings of higher risk among the male population are similar to other studies on drowning from other countries^3,17,18.

Individuals aged over 60 years were found to be 3.5 times at a higher risk than those aged between 18 and 60 years. The reasons behind that could be due to lack of a water supply in rural areas; therefore, people use natural water bodies as a source of water for daily regular activities and older populations are not under supervision. Similar findings were also observed in a study conducted among US populations between 1999 and 2010¹⁹.

Drowning is always sudden, unexpected and often fatalities occur at the scene of the water bodies. As a result, drowned individuals need emergency medical support on the site immediately when rescued from the water. Like most developing countries, emergency medical help is absent, particularly in rural areas, of Bangladesh^20,21. In this study, 61.5% of the drowning incidents ended with fatality at the scene of drowning. Findings in Finland suggested that around 24% causalities ended with fatality at the scene²². In addition, of those who were rescued alive (38.5%) from water bodies only 20% sought medical care from the hospital. This suggested that rural populations do not consider receiving medical care following drowning. The study findings show that among the drowning fatalities 56.1% took place in water bodies that were over 20 meters far the household, whereas the same survey finding shows that about 80% of child fatalities due to drowning took place within 20 meters of the household²³. In rural Bangladesh, households are located near water bodies so that getting water is easy for daily household needs. As a result exposure to water is very high for both adults and children.

As in most developing countries, injury incidences are poorly reported to the police station by the relatives of the victims²⁴. The survey findings identified that only 25% of cases were reported to the police station following drowning fatalities. Drowning is not a new event concerning injury, like road traffic or machine injury, instead it is an issue that has occurred for thousands of years among populations living near water sources. Rural populations consider drowning as a part of a natural death and pre-decided ‘God’s will²⁵; as a result relatives of the drowning victims start the burial process immediately after fatal drowning occurs. Unless the drowning incident was intentional, relatives of the victim do not report the death to the police station or any other agencies to avoid further investigation about the death.

Many high income countries reduced drowning rates by introducing effective interventions¹. This paper describes the epidemiological situation of adulthood drowning in Bangladesh so as to explore people’s perceptions on drowning and to design effective interventions for the adult population further research is needed. In addition, this paper might draw the attention to the policy makers to design possible preventive measures.

Conclusions

Adult drowning is an important, but neglected, public health issue in Bangladesh, especially in populations living in the rural areas. Every year a significant number of unwanted and preventable adult drowning fatalities occur in Bangladesh. The current survey findings might help policy makers and scientists to understand the epidemiology and the risk factors leading to adult drowning in Bangladesh.

Data availability

BHIS data is stored at the Department of Public Health Science and Injury Prevention of CIPRB. Due to sensitivity of the data (contains identifying information), permission is required from the ethical committee for sharing data with a third party. Data can be requested from the Department of Public Health Science and Injury Prevention of CIPRB, who will contact the ethical review committee to gain approval to share the data. The conditions for gaining data access are a formal request with a clear objective and formal permission from the ethical committee. Please contact Dr Saidur Rahman Mashreky (mashreky@ciprb.org) in order to request the data.

Ethics and consent

Ethical approval for the collection of the BHIS data was obtained from the Ethical Committee of the Institute of Child and Mother Health, Dhaka (ref: ICMH/ECR/2002/009). During conduction of the survey all participants were informed about the objectives and benefits of the study. As the sample was over 800,000 individuals, only oral consent was obtained from each of the household head before proceeding the interview.