NCDs have become a major public health challenge in Bangladesh with a higher prevalence of double burden . This study focused on the estimation of age-standardized prevalence and factors associated with the of DM, HT and comorbidity (both DM and HT) among adult population in Bangladesh. Similar to the previous studies [15, 29–33], we found that females, aged over 35 years and higher, having overweight or obesity, being from households with rich wealth status were the significant risk factors associated with any of the NCDs studied. While participants’ current working status were associated with the lower odds of having NCDs. The findings of this study revealed that the overall age-adjusted prevalence of DM and HT was 11.55% and 35.04%, respectively, and 6.16% had comorbidity which are higher than the prevalence of DM (11.0%), HT (29.7%), and comorbidity (4.5%) among Bangladeshi adult population found in 2011. Though the DM prevalence is almost consistent, the prevalence of HT was higher than the overall prevalence (age-adjusted) of South-Asian countries (20.1%) and other low-middle-income countries (31.5%). These increasing pattern and higher prevalence of NCDs indicate that Bangladesh is in a great challenge in controlling as well as to reduce the burden of chronic diseases. This rising burden could be due to the epidemiological transition of Bangladesh like life expectancy at birth , increasing number of ageing population, rapid urbanization, lifestyle changes and physical inactivity . In order to curve the burden of these NCDs, the government of Bangladesh should focus on implementing the awareness, prevention and control programs, since such type of programs in Bangladesh are insufficient reported by previous study .
This study observed that females were more prone to be hypertensive compared to their male counterparts. This finding aligns with other similar studies conducted in Bangladesh [29–33]. Various biological and environmental factors could be responsible for this higher prevalence among females . In addition, several studies have shown that stress is often linked to high blood pressure, and middle-aged women may be more susceptible to have higher stress especially during menopause [37, 38]. Again, prevalence of overweight and obesity were found to be higher among females than males previously , and an increased BMI might also be associated with the elevated blood pressure . Previous literatures have also shown that differences in physiological and behavioral characteristics between males and females may contribute to these differences [40, 41].
We found a positive relationship between age and prevalence of NCDs where the risk of NCDs were increased with the increase of age. Age is sometimes considered as an irreversible risk factors of different NCDs [42–44]. Presently, Bangladesh is undergoing a demographic change which may result in a large proportion of the elderly in this country . Evidence shows that older people are at greater risk of having different chronic conditions like diabetes, hypertension, overweight/obesity, etc.,[24, 42, 44, 45]. These diseases affect each other's outcomes, and also they have many common risk factors that can lead to more serious complications [24, 42]. The higher tendency of these NCDs among older adults could be due to various health problems happen among older people and their lifestyle like poor nutritional condition, stiffness, sodium intake, physical inactivity, and lower immunity [42, 43, 46].
Participants with BMI higher than normal were at higher risk of suffering chronic diseases; such positive link between higher BMI and NCDs are well-established and can be justified by the previous evidence [15, 30, 32, 33]. Bangladesh is undergoing a greater challenge in controlling the NCDs while the prevalence of overweight and obesity is uprising [47, 48]. Along with the nutritional changes in Bangladesh, the steady rise in BMI has serious consequences related to premature NCD-related illness and death. Various metabolic and genetic factors might be responsible for such positive association [49–51]. Thus, controlling and preventing the NCDs along with overweight/obesity would be fruitful since prevention and controlling measures of overweight/obesity and other chronic conditions are almost similar . Thus, simultaneously controlling these conditions will have a significant positive impact on the health system in Bangladesh [52, 53].
As found in the previous literatures [29, 54], present study found that people involved in any type of work were at reduced risk of diabetes and comorbidity. Involving in work increases the physical activity and several studies found a negative association between moderate/higher levels of physical activities and chronic diseases [55, 56]. Physical activity increases the use of oxygen throughout the body and maintains blood glucose levels . In addition, physical activity also reduces the adverse consequences of many chronic diseases like diabetes ; hence, promoting physical activity is crucial in controlling diabetes and other chronic diseases [59, 60].
Compatible with earlier studies [15, 29], we observed that individual with higher economic status were at increased risk of having DM and comorbidity (coexistence of both DM and HT) compared to those belong to poor households. Another Bangladeshi study identified that the odds of having DM and comorbidity were higher among people from rich families  which is similar to what we found in this study. A plausible reason for this finding might be due to some factors including lower physical activity, sedentary lifestyle, and higher overweight/obesity among people from richest quintile [29, 61]. Besides, people with relatively low socio-economic status in Bangladesh are employed in more laborious work that may keep them away from sedentary lifestyle and they are also supposed to eat foods with less amount of calories [62, 63].
Similar to previous studies [64, 65], we also found that smoking is positively associated with NCD and HT. It is well-established by previous several global studies [64, 65] that unhealthy lifestyle like smoking is associated with increased risk of chronic diseases. Though available evidence from prospective studies already identified smoking as a confirmed risk factor for hypertension and other NCDs , the relationship between chronic smoking and raised blood pressure is still controversial . Furthermore, smoking can have a greater detrimental effect on central blood pressure by affecting arterial stiffness and wave reflection that may explain the causal relationship between smoking and developing hypertension.
This study's strengths and limitations have been acknowledged. The generalizability of the findings for Bangladesh is a strength of this study, as this survey included nationally representative data from all divisions. In addition, appropriate statistical procedures were used to assess the sample's weighted prevalence of hypertension. The study's limitations are stated in a fair manner. No causality could be established due to the cross-sectional design, and the participants' blood pressure was taken three times in one day.