Chronic disease epidemiology presentation

1. Chronic Diseases
Epidemiology
By Ammar Bishaw

2. Definitions
• Chronic disease is a medical condition or disease, which
is not infectious, with long duration and relatively slow
progression
(WHO,2017)
Chronic conditions are characterized by the following:
– Do not result from an (acute) infectious process
– Are “not communicable”
– Cause premature morbidity, dysfunction, and reduced
quality of life
– Usually develop and progress over long periods 2

3. Cont…
• Research in the chronic disease
epidemiology unit addresses the etiology,
prevention, distribution, natural history,
and treatment outcomes of chronic health
disorders such as: Cancer, Cardiovascular
disease, Chronic Respiratory disease.

4. •So many Chronic disease studies were
conducted in early 1930s.
•In 1950 Research on smoking and
lung cancer was done which is
considered a landmark in the history
of chronic disease epidemiology.

5. History
• In 1950, Doll and Hill, in England, and Wynder and
Graham, in the United States, published substantial
case-control studies that implicated the use of
tobacco as a major risk factor for the disease. A
controversy developed over the credibility of this
finding and was increased in 1954 when a cohort
study by Doll and Hill and another by Hammond and
Horn each gave estimates that the risk of lung cancer
was greatly increased among smokers relative to the
risk among comparable non-smokers.

6. Some Chronic diseases
Cardiovascular Diseases
Cancer
Chronic Respiratory Diseases
Diabetes
Hypertension
Overweight/obesity
CLD

8. Non-communicable diseases and
conditions in Ethiopia, GBD 2019
8

9. Study Designs
• Cross-sectional
- Good for Prevalence study
- Quick and cheap
- Problem in Temporality
• Cohort Study
- Expensive, time consuming since long latency
period
• Case-control
- Better design for analytic study
• case reports and case series- For Cancer studies

10. Bias in Chronic disease
epidemiology
• Neyman bias (prevalence-incident case bias)
- extremely sick individuals or extremely healthy
individuals are excluded from the final results of
the study which may lead to biased results.
• Selection bias
- Hospital –based sampling means miss all the
cases who don't attend those hospitals or seek
care during the study
• Survival bias
• Recall bias

11. Primary prevention
• Policies that promote government-wide action
against NCDs
• Stronger anti-tobacco control
• Promoting healthier diets
• Physical activity
• Restrict Alcohol use
• vaccinate against HPV and hepatitis B virus;
• control occupational hazards;

12. Cardiovasculardiseaseresearchesin Ethiopia
12
Table 1.
Literature review of the prevalence of cardiovascular diseases from hospital-based studies in Ethiopia, 1962-2006
Year Author Region in Ethiopia
Urban/Rural
Targets Sample-size Outcome Prevalence (%)
Diagnostic criteria
2011 Misganaw et al. (14)
AA Urban Community-based (>15 years)
3,709 deaths Cardiovascular disease 24 Verbal autopsy
2006 Melaku Z et al. (21)
AA Mixed All age-groups 3,548 MICU admission AMI disease 9.8 Physicians’ diagnosis
2006 Andarge B et al. (18)
Oromia Mixed All age-groups 3,99 all admission Cardiac disease 12 Physicians’ diagnosis
2004 Fantahun Met al. (15)
Amhara Mixed Community-based (all age-groups)
200 deaths Cardiovascular diseases 6.5 Verbal autopsy
2001 Mamo Y et al. (22)
Oromia Mixed All age-groups 2,313 MICU admission AMI disease 8.8 Physicians’ diagnosis
1995 Hussein K (20)
Oromia Mixed >10 years 1,440 all admission Cardiovascular diseases 10.5 Physicians’ diagnosis
1994 Pauletto P et al. (11)
Oromia Rural >15 years 5,277 outpatients Hypertension/ heart disease 0.5 Physicians’ diagnosis
1988 Bahta Y et al. (31)
AA Mixed >10 years 917 MICU admission Cardiovascular disease 11.7 Physicians’ diagnosis
1988 Bahta Y et al. (31)
AA Mixed >10 years 917 MICU admission Cerebrovascular accident 8.1 Physicians’ diagnosis
1988 Bahta Y et al. (31)
AA Mixed >10 years 917 MICU admission Congestive heart failure 5.6 Physicians’ diagnosis
1983 Tekelu B (13)
AA Urban Adults 2,145 outpatients Hypertension/ heart disease 6.7 Physicians’ diagnosis
1982 Lester FT (12)
AA Mixed >60 years 200 medical admission Cardiovascular disease 31 Physicians’ diagnosis
1982 Abraham G (19)
AA Mixed 13-82 years 5,667 medical admissions Cardiovascular disease 6.6 Physicians’ diagnosis
1976 Habte-Gabr E et al. (16)
Amhara Mixed All age-groups 3,611 all admissions Cardiovascular disease 3 Physicians’ diagnosis
1976 Habte-Gabr E et al. (16)
Amhara Mixed All age-groups 238 deaths Congestive heart failure 2.5 Physicians’ diagnosis
1974 Lainovic D (26)
AA Mixed >15 years 9,330 medical admissions Cardiovascular disease 6 Physicians’ diagnosis
1973 Lester FT (12)
AA Mixed >11 years 2,103 outpatients Hypertension/heart disease 12 Physicians’ diagnosis
1971 Teklu B et al. (34)
AA Urban 17-64 years 460 outpatients Cardiovascular disease 24 Physicians’ diagnosis
1970 Pavlica D (23)
AA Mixed >16 years 3,922 medical admissions Cardiovascular disease 4.4 Physicians’ diagnosis
1970 Pavlica D (23)
AA Mixed >16 years 3,922 medical admissions Hypertension/heart disease 2.5 Physicians’ diagnosis
1970 Pavlica D (23)
AA Mixed >16 years 3,922 medical admissions Rheumatic valvular disease 0.7 Physicians’ diagnosis
1962 Blahos J et al. (9)
Harrar Mixed All age-groups 11,170 outpatients Cardiovascular disease 7.2 Physicians’ diagnosis
1962 Blahos J et al. (9)
Harrar Mixed All age-groups 11,170 outpatients Hypertension/heart disease 2.4 Physicians’ diagnosis
AMI=Acute myocardial infarction
MICU=Medical Intensive Care Unit

13. Thank you