Cause and age-related mortality trends in Bangladesh (2000-2008)
Mortality trends are important to demographers because they present a useful way of examining mortality differentials and their principal causes across populations. It has been reported that generally mortality rates in Bangladesh have reduced notably over recent decades1. However, deaths caused by chronic diseases are rising at an alarming rate1. There is a rapid rise observed in the burden of non-communicable diseases (NCDs) worldwide. Demographic transition and changing lifestyles among people are important factors for these kind of health problems2. The World Health Organization (WHO) has predicted that, by 2020, two-thirds of the world’s global burden of disease will be caused by non-communicable conditions3. In 2005 it was reported that non-communicable diseases such as heart disease, stroke, diabetes mellitus, cancer, and chronic respiratory diseases were responsible for 59% of the 57 million deaths yearly and 46% of the total burden of disease, globally3.
The burden of NCDs has been showing an increasing trend in South Asia, where almost half of all deaths in Asia and 46% of global burden of disease is attributable to these diseases5. It was observed in much of sub-Saharan Africa that the leading risks were those associated with poor quality of life6. Cardiovascular disease is a major non-communicable disease, taking almost 17 million lives each year7. It has been observed that decreasing primary risk factors such as inadequate nutrition, physical inactivity, smoking etc. can decrease death rate significantly7. Alam et al.8 investigated total deaths of adults with increasing age in Bangladesh and found communicable diseases responsible for 18% of overall deaths and NCDs responsible for 66%8. The NCDs included those caused by the circulatory system (35%), respiratory system (10%), digestive system (6%), neoplasms (11%) and endocrine and metabolic disorders (6%)8.
There are relatively few published studies about mortality, especially for NCDs, in developing countries like Bangladesh. It is therefore a timely necessity to categorize the country’s mortality data by cause of death, sex and age group. The aim of this study is to analyze mortality trends in Bangladesh. These will help in the development of strategies regarding the approach of the health sector to disease control. It is also important to increase awareness about which diseases will cause further burden in Bangladesh, in order to supply the suitable drugs.
Materials and methods
This study used vital registration, maternal and child health data collected from Matlab, a rural area of Bangladesh, in 2000, 2004 and 2008. The data were gathered and published by Health and Demographic Surveillance System of ICDDR,B. In 2000, 2004 and 2008, the surveys counted 218579, 224476 and 222218 individuals, respectively. In 2000, the surveys counted 106370 male individuals and 112209 female individuals. In 2004, the surveys counted 107439 male individuals and 117037 female individuals. In 2008, the surveys counted 103579 male individuals and 118639 female individuals.
Mortality rates
Mortality rate is a measure of the number of deaths in a population. It is expressed as number of deaths per 1000 individuals per year. Cause-specific mortality rate is the number of deaths from a particular causes of disease in a population during a fixed time period.
Results
Table 1 shows total deaths and death rates in Bangladesh in 2000, 2004, and 2008. Regarding causes of death, neonatal and maternal diseases (D1), showed a decreasing trend both in males and females. Communicable diseases (D2) also showed decreasing trend. Non-communicable diseases (D3) showed an increasing trend, almost doubling its victim count between 2000 and 2004. Injuries and miscellaneous causes (D4) showed a statistically significant declining trend. The overall male death rate from year 2000 to year 2004 represented a growing trend and reached from 7.52 to 7.86, falling back to 7.49 in 2008. Similar trends can be seen for female death rates.
| Year | Sex | |||
|---|---|---|---|---|
| 2000 | Male | |||
| Fem… | 112… | |||
| 2004 | Male | |||
Table 1. Male and female mortality rates in Matlab, Bangladesh (2000–2008).
It is observed that males have a higher mortality rate than females in 2008. Also, the total number of deaths from non-communicable diseases was significantly higher than in the rest of the disease categories for both sexes. After analyzing Table 2, it has come to our attention that the percentage of male deaths was higher than female deaths across all years.
Table 3 provides age specific death rates for males in Bangladesh in 2000, 2004, and 2008. Infant mortality was highest in 2000, at 15 per 1,000 children. There was a gradual decline in rate of infant mortality from 2000 to 2008, with 11 per 1000 children in 2004 and 9 per 1000 children in 2008. The death rate was also declining for the 0–14 age category from 2000 to 2008. On the contrary, the 15–59 age group showed increasing death rates from 2000 to 2008, with 2.81 per thousand in 2000, 2.99 per thousand in 2004 and 3.04 per thousand in 2008. Finally, natural trends were observed in the 60+ age groups. Most people died at that age. Table 4 shows that for the 60+ age groups, female mortality was lower than male mortality in Bangladesh. Female death rates at ages of 60+ were 39 per thousand in 2000 and 42 per thousand in 2004. Among males, death rates at ages of 60+ were 48 per thousand males in 2000 and 54 per thousand males in 2004. The trends remained the same for 2008. This was also true for the age group 15–59. There was no statistically significant difference in death rates between males and females of the age group 0–14. Infant mortality was highest in 2000 amongst this age group, at 15 per thousand both in male and female infants. Female infant mortality exhibited a gradual decline over the years from 2000 to 2008, similar to male infant mortality. Infant mortality rate was 11 per thousand in 2004 and 6 per thousand in 2008.
Table 5 shows that among the total male NCD related deaths in year 2004, 232 (43%) fall under the category of circulatory related disease, 82 (15%) of them fall in the neoplasm group, and 78 (14%) of them were respiratory related. Then, 59 (11%) male NCD related deaths fall under the category of digestive disease, 47 (9%) under endocrine disorder, 16 (3%) under neuro-psychiatric, 17 (3%) under genito-urinary and 9 (2%) under other NCDs. In the year 2008, 297 (54%) of NCD related deaths fall under the category of circulatory related disease, 96 (18%) fall in the neoplasm group, and 52 (10%) of them were respiratory related. Then, 40 (7%) fall under the category of digestive disease, 30 (5%) under endocrine disorder, 8 (1%) under neuro-psychiatric, 16 (3%) under genito-urinary, and 4 (1%) under other NCDs.
| Typ… | Fre… | |||
|---|---|---|---|---|
| Neo… | 82 | |||
| Con… | 0 | |||
| End… | 47 | |||
Table 5. Male deaths from non communicable disease in the years 2004 and 2008.
In Table 6, it can be observed that among the total female NCD related deaths in 2004, 234 of them (54%) fall under the category of circulatory related disease, 46(10%) of them fall in the neoplasm group, and 34 (8%) of them were respiratory related. Then, 51 (12%) female NCD related deaths fall under the category of digestive disease, 29 (6%) under endocrine disorder, 13 (3%) under neuro-psychiatric, 17 (4%) under genito-urinary and 12 (3%) under the other non-communicable disease category. Among the total female respondents, 282 (61%) of NCD related deaths in 2008 fall under the category of circulatory related disease, 51 (11%) fall in the neoplasm group and 52 (11%) of them were respiratory related. Then, 21 (4%) female NCD related deaths fall under the category of digestive disease, 31 (7%) under endocrine disorder, 8 (2%) under neuro-psychiatric, 13 (3%) under genito-urinary and 5 (1%) under the other non-communicable disease category.
| Dis… | Fre… | |||
|---|---|---|---|---|
| Neo… | 46 | |||
| Con… | 0 | |||
| End… | 29 | |||
Table 6. Female deaths from non communicable disease in the years 2004 and 2008 (ICDDR, B).
Table 7 shows the distribution by age group of male circulatory and neoplasm related deaths. Circulatory system related diseases and neoplasms greatly affected the age groups 45–59 and above. Circulatory system disease related deaths were highest (34.01%) in the age group 70–79, and neoplasm related deaths were highest (34.38%) in the age group 60–69. The asymptotic significance level was 0.000. Given that the null hypothesis is rejected when the p-value is less than 0.05, this indicates a strong relationship between age and incidence of disease in men. (Table 8).
| Age gr… | Circul… | |||
|---|---|---|---|---|
| 0–4 | 0.00% | |||
| 5–14 | 0.34% | |||
| 15–29 | 1.35% | |||
Table 7. Male circulatory and neoplasm related deaths, distributed by age group, in Matlab (2008).
| Value | ||||
|---|---|---|---|---|
| Pear… | 35.0… | |||
| Like… | 36.7… | |||
| Line… | 30.4… | |||
Table 8. Chi-Squared tests between circulatory and neoplasm related deaths by age groups for males in Matlab, 2008.
Table 9 shows the distribution by age group of female deaths caused by three major NCDs: circulatory system related diseases, neoplasms, and respiratory related diseases. Similar to what was observed in the male population, circulatory system related diseases, respiratory related diseases, and neoplasms had a greater effect on age groups 45–59 and above. Circulatory system disease related deaths were highest (38.65%) in the age group 70–79, neoplasm related deaths were highest (29.41%) in the age group 45–59 and respiratory related deaths were highest (32.69%) in the age group 60–69. The asymptotic significance level was less than 0.05 (Table 10). Given that the null hypothesis is rejected when the p-value is less than 0.05, this indicates a strong relationship between age and incidence of disease in females (Table 10).
Discussion
In 1990, worldwide and regional cause-of-death patterns were measured across age groups. It was found that 98% of all deaths in children below 15, 83% of all deaths in the 15–59 age group, and 59% of all deaths in the 70+ age group were occurring in the developing world9. The disease mortality pattern in elderly patients of a Nigerian teaching hospital was studied from January 2007 to December 2011. A total of 3,002 elderly (>65 years) people were admitted, of which 561 died. Among the population, 317 were male and the rest were females. Cerebrovascular disease was the top cause of death (25.1%). The second and third major causes of death were malignancies (15.2%) and diabetes mellitus (8%)10. A cross-sectional study involving 535 inhabitants of Sokoto in Nigeriato displayed the prevalence and pattern of non-communicable diseases. The participants were overweight, obese and morbidly obese, and represented 12.3%, 6.7% and 0.9% of the population, respectively. The prevalence of pre-hypertension and hypertension was 8.5% and 30.2%, respectively11.
Deaths from non-communicable diseases represent a rising trend. Our results support the finding that non-communicable diseases are imposing a sizeable and growing public health burden globally12–18. Vital registration, maternal and child health data was collected from Matlab, Bangladesh, in 2000, 2004 and 2008. The data were collected and published by Health and Demographic Surveillance System of ICDDR, B. Among the total male NCD related deaths in year 2004, 232 (43%) fall under the category of circulatory related disease, 82 (15%) of them fall in the neoplasm group, and 78 (14%) of them were respiratory related. Then, 59 (11%) male NCD related deaths fall under the category of digestive disease, 47 (9%) under endocrine disorder, 16 (3%) under neuro-psychiatric, 17 (3%) under genito-urinary and 9 (2%) under other NCDs. In the year 2008, 297 (54%) of male respondents fall under the category of circulatory related disease, 96 (18%) fall in the neoplasm group, and 52 (10%) of them were respiratory related. Then, 40 (7%) deaths fall under the category of digestive disease, 30 (5%) under endocrine disorder, 8 (1%) under neuro-psychiatric, 16 (3%) under genito-urinary, and 4 (1%) under other NCDs.
Among the total female respondents, 234 (54%) of NCD related deaths in 2004 fall under the category of circulatory related disease, 46 (10%) of them fall in the neoplasm group, and 34 (8%) of them were respiratory related. Then, 51 (12%) female NCD related deaths fall under the category of digestive disease, 29 (6%) under endocrine disorder, 13 (3%) under neuro-psychiatric, 17 (4%) under genito-urinary and 12 (3%) under the other non-communicable disease category. Among the total female respondents, 282 (61%) of NCD related deaths in 2008 fall under the category of circulatory related disease, 51 (11%) fall in the neoplasm group and 52 (11%) of them were respiratory related. Then, 21 (4%) female NCD related deaths fall under the category of digestive disease, 31 (7%) under endocrine disorder, 8 (2%) under neuro-psychiatric, 13 (3%) under genito-urinary and 5 (1%) under the other non-communicable disease category. There were more male deaths due to neoplasms and more and female deaths due to circulatory related disease.
It is recognized that a huge portion of the population will die because of non-communicable diseases. The number of deaths rapidly increases year by year12,19. Males of ages 45 and above were greatly affected by circulatory system related diseases and neoplasms. Circulatory system related deaths were highest (34.01%) in the 70–79 age group. Neoplasm related deaths were highest (34.38%) in the 60–69 age group. Similar patterns were observed for females. Circulatory system related diseases, respiratory related diseases and neoplasms greatly affected females of the 45–59 age group and above. The highest percentage (38.65%) of circulatory system related deaths was found in the 70–79 age group; neoplasm related deaths were highest (29.41%) in the 45–59 age group; and the highest percentage (32.69%) of respiratory related diseases was found in the 60–69 age group.
Conclusions
This study recognized that a huge number of people die because of non-communicable diseases. This number increases year by year at a large scale. Deaths from circulatory related diseases were significantly higher than from other non-communicable diseases. In females, the mortality rate was very high for these. The second major cause of death was from neoplasms for the male population in 2008. Circulatory system related diseases and neoplasms greatly affected the 45–59 age groups and above. For females, the death rate was very high for respiratory related diseases. Females were affected by non-communicable diseases at a younger age than males. Circulatory system related diseases, neoplasms and respiratory related diseases are the top three NCDs which have massive impact on the health of the population, and should therefore be given the utmost attention. These three NCDs and their associated risk factors should be targeted in all public health awareness programs.
The national policy and action plan should take these points into consideration, and focus on improving basic education and expanding public health systems to raise awareness. Mass media outlets such as television, newspapers, radios, and the internet can play an effective role to promote consciousness and alert people to the dangers posed by NCDs. Awareness campaigns can positively modify attitudes. Finally, the Ministry of Health and Family Welfare should train more personnel, achieve national coverage and promote more research on the subject, thus ensuring high standards are kept.
Data availability
Raw datasets have not been made available at the request of the ethics committee in order to maintain participant confidentiality. This data is stored at the Department of Statistics, University of Rajshahi, and is available upon request. Please contact the 1st author (Aziza Sultana Rosy Sarkar, email: asrosy2012@gmail.com) for further information.
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