This study examined the prevalence and predictors of betel quid chewing in rural Bangladesh and its relationship to blood pressure. The study found that betel quid chewing was common, particularly among older individuals and those of lower socioeconomic status. Chewing betel quid without tobacco was associated with higher systolic and diastolic blood pressure. The results suggest betel quid chewing may contribute to cardiovascular disease burden in Bangladesh. Limitations included lack of data on chewing frequency and potential residual confounding. Strengths included a large population-based cohort and high follow-up rates. The findings have public health implications and could inform interventions to address this growing health problem.

1. Critical Analysis
EVA ZIMMERMAN
FUNDAMENTALS OF EPIDEMIOLOGY
THURSDAY, 10 NOVEMBER 2016
Betel Quid Chewing in Rural Bangladesh:
Prevalence, Predictors and Relationship
to Blood Pressure
Julia E Heck,1* Erin L Marcotte,1 Maria Argos,2 Faruque Parvez,3
Alauddin Ahmed,4 Tariqul Islam,4 Golam Sarwar,4 Rabiul Hasan,4
Habibul Ahsan2,3 and Yu Chen5

2. Critical Questions
1. What gap in knowledge was meant to be filled?
• “Few population-based estimates exist on the prevalence and determinants of betel chewing
in Bangaldesh”…” previous estimates were not available on use among women.”
• Lack of literature on the relation between betel quid chewing and cardiovascular health
2. What is the hypothesis and aims of the study?
• Aim: “The purpose of this investigation was to report the use of betel quid in a large cohort
of Bangladeshi men and women and to assess the associations of betel quid with socio-
demographic factors, body mass index (BMI) and blood pressure.”
• Null Hypothesis (H0): Betel quid chewing is not determined by certain socio-demographic
predictors, and is not associated with an increase in body mass index (BMI), nor various
deleterious effects on cardiovascular health.
• Alternative Hypothesis (HI): Betel quid chewing is determined by certain socio-demographic
predictors, and is associated with an increase in body mass index (BMI), along with various
deleterious effects on cardiovascular health.

3. Critical Questions
3. What were the methods used (including study design, study population, power
calculations, sample size determination, approach and techniques)?
• Design: Population-Based Prospective Cohort Study
• Study Population: Married men and women, aged 18-75 years at the initial interview, who
have lived in the same bari (cluster of homes) for the previous 5 years
*Inclusion criteria were chosen to ensure greater stability of residence
• Power/Sample Size Calculations: No mention of power or sample size calculations; Final
sample size of 19 934 + 95% confidence interval
• Approach: After obtaining informed consent, data were collected by standardized in-person
interview by trained interviewers. Clinical evaluations were done by local trained physicians.
• Appropriate?
4. What are the results?

8. Critical Questions
5. What are the key conclusions of the study and are they justified?
• Conclusion:
• There is considerable burden of betel quid chewing in Bangladesh
• Betel quid chewing was associated with older age and lower socioeconomic status
• Chewing betel quid without tobacco was related to increases in systolic and diastolic
blood pressure and to general and systolic hypertension
• Betel quid chewing may be contributing to the burden of vascular diseases in
Bangladesh
• Justification: presuming an accurate calculation of the study power, the findings are
justified for this particular population in this particular setting

9. Critical Questions
6. What are the confounders?
• Confounders adjusted for:
• Baseline age, sex, BMI
• Socio-economic factors (educational attainment, occupation, religion, marital status, land
ownership)
• Change in weight, use of hypertensive medications, and pack-years of smoking over
follow-up period
• Reliability of blood pressure measurements (separate reliability study on 61 subjects)
• “White coat hypertension”
• Unadjusted Confounders:
• Use of hukka or guul (data on these substance was not available for expansion cohort)
• Possibility of residual confounding

10. Critical Questions
7. What are the limitations of the study and their implications?
• The study was not designed with a focus on betel quid
- Quantity chewed
- Changes in chewing frequency over time
• Lack of additional health information (cholesterol or physical activity levels)
• Lack of information on family history of hypertension
• Generalizable?

11. Critical Questions
8. What are the study’s strengths and their particular value to the current
literature?
• Large cohort size; 2000-01 cohort recruited 11 746 individuals, 2006-08
cohort recruited 8 287 individuals
• Overall response rate was 97.5%
• Follow-up data collected every two years
• Reported a population-based estimate on the prevalence and determinants
of betel quid chewing
• Association of betel quid with cardiovascular health; results were in line with
those of other Bangladeshi studies

12. Critical Questions
9. What are the public health implications of the findings?
• Betel quid is chewed by 600 million people worldwide; its use is particularly
common in Asia and in migrant communities in the West
• Betel quid chewing may be contributing to the increasing burden of vascular
disease in Bangladesh
• Interventions in the study should be designed to address this growing health
problem
10. What is the quality of the discussion, and does it lead to other investigations
that expand the field?
Discussion is of good quality and suggests:
• There is a generational shift towards lower betel quid use
• Are these results generalizable to other populations?