Alarming prevalence and clustering of modifiable noncommunicable disease risk factors among adults in Bhutan: a nationwide cross-sectional community survey

Non-communicable diseases (NCDs) kill 38 million people each year, and 75% of these deaths occurs in low- and middle-income countries [1]. Among the NCD-related causes of deaths almost half are due to cardiovascular diseases, a quarter to cancers, one-fifth due to diabetes, and one-tenth to respiratory diseases [1]. By 2020, it is estimated that 80% of the global burden of the diseases will be due NCDs, causing seven in ten deaths [2].

Behavioral risk factors such as tobacco use, unhealthy diet, physical inactivity, high salt consumption, and harmful use of alcohol lead to biological risk factors such as obesity, hypertension, hyperlipidemia, and impaired fasting glycaemia, which ultimately lead to NCDs. Clustering of risk factors in the same individual or population is common and this further increases the risk of NCDs [3].

The World Health Organization (WHO) in 2014 reported that 56% of the deaths in Bhutan were caused by NCD [4]. The World Bank reported that Bhutan by 2025 will have 7.3% of people above 65 years of age, which will increase the burden of NCD, since the prevalence of NCDs increases with age [5]. Bhutan is currently facing a double burden of NCDs and communicable diseases, and the administrative data collected by the Ministry of Health indicates rising trends of NCDs [6]. In line with this and the global action plan on NCD of achieving a 25% reduction in premature mortality from non-communicable diseases (NCDs) by 2025 (the 25 × 25 target) [7], Bhutan has developed the National Action Plan on NCD [8], and has rolled-out WHO Package of Essential NCDs (PEN) in the country [6]. However, the country requires robust data for planning and allocation of resources. In view of this, the Ministry of Health undertook a nationwide survey in 2014 using the WHO STEP-wise approach [9]. The aim of the survey was to determine the prevalence of key behavioral and biological risk factors of NCDs in the adult population (aged 18–69 years) of Bhutan.

The survey report did not indicate how the NCD risk factors are associated with different socio-demographic characteristics, and whether is there any pattern in clustering of risk factors [10]. Therefore, this study aimed to determine the distribution and clustering of modifiable non-communicable disease (NCD) risk factors among adults in Bhutan and their demographic and social determinants.

This secondary analysis of the first nation-wide survey data on NCD risk factors in Bhutan is the first to describe the distribution and clustering of modifiable behavioral and biological risk factors. Not only was the prevalence of most risk factors found to be high in this population, but also clustering of risk factors was widely prevalent. Almost every adult Bhutanese consumes high amount of salt. Two out of three adults has an unhealthy diet, one in three is overweight and one in three has raised blood pressure. Despite a national ban on tobacco since 2004, one in three adult men does smoke or uses smokeless tobacco, and this has been already described [17]. The median number of risk factor per adult was three, while the most commonly clustered factors was a combination of high salt intake, unhealthy diet, overweight and high blood pressure.

The mean amount of salt consumed is 9 g per day, which is almost double the amount of what WHO recommends (<5 g per day) [18]. Bhutan however is not much different in terms of high salt intake compared to other countries. A study conducted in Shandong province of China found high salt intake among 92% of its adult population [19], while most countries in South East Asia Region consume more than 10 g/day of salt – Sri Lanka 9–11 g/day; Nepal 10–13 g/day; Indonesia 15 g/day; Bangladesh 17 g/day [20].

A number of studies have indicated that salt intake is highly associated with development of hypertension –one of the NCD biological risk factors [21–24], this may partly explain the high prevalence of raised blood pressure as indicated by this study (36%). Therefore, one of the key areas of intervention for addressing the growing burden of NCD in Bhutan should be reduction of salt intake. The successful salt intake endeavors could save millions of dollar besides bringing enormous public health benefits. It has been calculated that reducing sodium intake to 2.3 g/day could save US$ 18 billion in annual US healthcare costs [25], and gold standard national sodium reduction program would cost 1–2% of hypertension program cost [20]; however population-based interventions apart from awareness campaigns are not commonly reported. A small-scale pilot study in South Korea has shown that educating restaurant owners and cooks to lower their own sodium intake to be a potential strategy for reducing the sodium contents of restaurant food [26]. However, more evidence is required to see whether this particular strategy would work in Bhutan as this survey reports that, respondents consumed on average only one meal per week that was not prepared at home [10].

Bhutan, being a mountainous country nestled in the Eastern Himalaya availability of fruits and vegetables are seasonal. Many respondents said that they eat plenty of fruits when it is available at their farm or locality and they don’t eat any fruit when it is not available. Given the harsh climatic conditions hardly anything grows in winter in most part of the country. People either depend on the imported fruits and vegetables which are often not accessible to many or they resort to traditional cuisine of potatoes and dried vegetables. Moreover, because of the self-imposed isolation from modern civilization up until 1960s Bhutanese had very little exposure to the latest evidence on healthy diet. Fruits were considered as a snack to be munched on if you find one, but not as a nutritious food. As a result, consuming the recommended five servings of fruits and vegetables on an average day was found to be uncommon among adult Bhutanese. Other WHO STEPS surveys from the region have found similar results, however in high-income countries the case has been different [27].

We found low physical activity (i.e. not meeting WHO recommended ≥150 min of moderate-intensity activity per week, or equivalent) to be low at 6% among the Bhutanese population, which is three time less than the global estimate for prevalence of physical inactivity among adults 23% [24]. This finding might be because 70% of respondents in the survey were from rural areas, where people have to do hard laborious work in the fields. The 2007 STEPS survey conducted only in the urban area of Thimphu (capital city) has found that approximately 60% were not attaining the minimum required physical activity. Those with education level above secondary have higher prevalence of low physical activity; this might be probably because those with higher education level live in urban areas. Numerous studies have found that the combination of unhealthy diet and low physical activity are associated with overweight and obesity, which ultimately are risk factors for diabetes and cardiovascular disease.

The clustering of 3 or more risk factors is higher among adults older than 40 years old and among urban residents. Since one risk factor seems to lead to another, it is important to tackle NCD risk factors at behavioral level. There have been reports from urban Indian, Brazilian, and North American populations on clustering of risk factors, especially cardiovascular factors among hypertensive patients [3, 28, 29]. A Bangladeshi secondary analysis of a national STEPS survey has found that that 38% of the population had at least three risk factors and clustering was associated with age, male sex, urban residence, quality of house and educational level. The clustering phenomenon may predispose to a higher burden of NCDs compared to populations with lower tendency of clustering, Nevertheless, this represents not only a public health challenge but also an opportunity; interventions targeting more than one risk factors and tailored to the needs of specific subgroups and populations may be combined and resources may be shared and used more efficiently.

This study has several strengths and limitations. First, the survey that the data were derived from was conducted at the national level and therefore the surveyed sample was representative of Bhutanese adults aged 18–69 years. Pilot tested & validated instruments were used and the survey enumerators where trained thoroughly on data collection. Supervisors were sent in the fields and spot checks were done, to minimize non-sampling errors. Second, since the response rate was very high (97%) and weighted analysis was used to adjust for the complex survey design, the findings can be extrapolated to the whole of Bhutan. Third, we have comprehensively assessed and modeled the socioeconomic factors associated with NCD risk factors and we looked at clustering patterns for the first time in the country. Lastly, we adhered to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines in conducting and reporting the study [30].

An important limitation of the study was the potential social desirability bias in self-reporting tobacco use and this was probably enhanced by the fact that the survey enumerators were health care providers and that tobacco products are banned and the use of tobacco in public is prohibited. The prevalence of smoking might have therefore been underestimated. Second, the sampling framework was based on the 2005 census when the urban to rural ratio was 30:70 but this might have changed at the time of the survey. The prevalence of high salt intake was calculated based on single spot urine sample rather than gold standard 24-h urine sample collection, which might have led to inaccurate estimation [31]. Lastly, our study has the inherited limitations of the cross-sectional design.

There are some recommendations that could be made based on the evidence produced by this study. First, this study highlighted the most prevalent modifiable NCD risk factors, their determinants and their clustering patterns and therefore it may inform the national NCD Division in priority setting and allocation of recourses. Second, as several of the prevalent risk factors are behavioral and tend to cluster, the public and high-risk sub-groups and populations should be educated through culturally appropriate and innovative public health messaging and mass media campaigns. Targeted interventions in educational institutions and places frequented by the youth should be initiated and strengthened in order to influence long terms positive life-style changes. Third, health advice and care should be given to patients of any NCDs or NCD factors during any contact with health care providers. Teachers and health care providers could be trained in counseling. Fourth, legislation and enforcement of existing legislation (such as the tobacco ban) should be strictly enforced. The Ministry of Health in collaboration with Ministry of Trade and Industry could set salt limits for the food industry in the country, as 1 in 10 adult Bhutanese consume processed food high in salt daily [10]. Finally, innovation and piloting should be encouraged and expanded; for example an initiative of the Ministry of Health (December 2016) to offer aerobics, yoga and table-tennis classes after office hours to the headquarter staff could be encouraged to expand to other ministries, sectors and corporate agencies.

The prevalence of modifiable behavioral and biological NCD risk factors was high among Bhutanese adults with a strong tendency of clustering. If a risk factor is identified at the level of the individual or the population, a rigorous assessment of other risk factors has to be made at both the clinical and public health settings. Lifestyle modifications at the population level are urgently required as several risk factors such as high salt intake, unhealthy diet, obesity, and high blood pressure were alarmingly high and frequently clustered. This represents an emerging public health threat to the population, the health system as well as the economy of Bhutan. Moreover there is a need to consider policy and socio-political and economic factors that have undermined global and national progress to address the rise of NCDs and their risk factors in Bhutan as elsewhere.