Epidemiology

EPIDEMIOLOGY OF CHRONIC NON COMMUNICABLE DISEASES (NCDs)

Asst Prof Dr Faris Al Lami MB,ChB MSc PhD FFPH

Non-Communicable Diseases

Includes all “traditionally” defined NCDs such as CVD, DM, cancer, chronic respiratory diseases, mental illnesses as well as injuries and violence

CHRONIC DISEASE

All impairments or deviations from normal which have one or more of the following characteristics : Permanent Leave residual disability Caused by a non-reversible pathology Required special training of the patient for rehabilitation Required long period of supervision, observation or care

The disability-adjusted life year (DALY)

The disability-adjusted life year (DALY) extends the concept of potential years of life lost due to premature death to include equivalent years of “healthy” life lost by due to states of poor health or disability.

The disability-adjusted life year(DALY)

DALYs for a disease or injury cause are calculated as the sum of the years of life lost due to premature mortality (YLL) in the population and the years lost due to disability (YLD) for incident cases of the disease or injury.

EPIDEMIOLOGIC TRANSITION

It is the general shift from acute infectious and nutritional deficiency diseases characteristic of under development to chronic NCDs characteristic of modernization and advanced level of development.

1. Demographic Changes

Decrease in infant mortality rate Decrease in fertility rate Both lead to Population aging

Rising Life Expectancy

WHO report, 1997

Epidemiologic Transition

Demographic transitions: Indicators over time (UK as an indicator for the ‘western’ Model) Mortality Rate Fertility Rate Birth Rate Size Population Age Population
Omran, Millbank Mem Fund Quart, 1971;49,215

2. Urbanization and Socioeconomic Transformation

Changes in community relationships Changes in life style Decreased concerns about moral beliefs Human mobility Expansion of education Participation of women in labor force

3. Changes in Nutritional pattern

Rapid increase in food energy availability and consumption Percapita food energy and protein availability had increased by 2 folds


Availability of: rice increased by 5 folds wheat increased by 8 folds sugar increased by 3 folds fat increased by 3 folds No increase in vegetables Slight increase in fruits Obesity is emerging as a major public health problem

4. Others:

Smoking epidemic Tobacco trends are not hopeful There are 1.2 billion smokers in the world Tobacco causes 4 million deaths per year, a figure that will increase to 10 million per year by the late 2020s The public health impact is widespread and increasing fast in developing countries

4. Others:

Increase in alcohol consumption Trends in alcohol use: steady increases in many developing countries with continued very high rates of being drinking in many east and central European countries. Sedentary life style

Burden of NCDs

The burden of chronic NCDs is rising rapidly and become a major challenge to global development. In all WHO regions (except Sub-Saharan Africa), NCDs today constitute the largest contributor to burden of diseases

Burden of NCDs

In 2002 WHO reported that major NCDs accounted for about 60% of global deaths and 47% of burden of disease. By 2020 these estimates are expected to rise to 73% and 60% respectively.

By 2020, 10 out the top 15 causes of DALYs lost will be attributable to NCDs, mental health and injuries/violence The top five positions will be occupied by: Ischemic Heart Disease, depression, road traffic injuries, cerebrovascular disease Chronic Obstructive Pulmonary Disease (COPD)

Annually, NCDs kill more than 36 million people Leading causes of NCD deaths Cardiovascular diseases (17.3 million) Cancers (7.6 million) Respiratory diseases (4.2million) Diabetes (1.3 million)

The top 10 leading causes of death by broad income group (2008)

World
Deaths in millions
% of deaths
Ischemic heart disease
7.25
12.8%
Stroke and other cerebrovascular disease
6.15
10.8%
Lower respiratory infections
3.46
6.1%
Chronic obstructive pulmonary disease
3.28
5.8%
Diarrheal diseases
2.46
4.3%
HIV/AIDS
1.78
3.1%
Trachea, bronchus, lung cancers
1.39
2.4%
Tuberculosis
1.34
2.4%
Diabetes mellitus
1.26
2.2%
Road traffic accidents
1.21
2.1%

NCD Burden of Disease

Source: Irina A. Nikolic, Anderson E. Stanciole, and Mikhail Zaydman, "Chronic Emergency: Why NCDs Matter," World Bank Health, Nutrition and Population Discussion Paper (2011).

Cardiovascular diseases (27%)

Infectious and parasitic diseases (17%)
Respiratory infections (10%)
Perinatal conditions (10%)
Malignant neoplasms (7%)
Respiratory diseases (4%)
Unintentional injuries (7%)
Digestive diseases (4%)
Intentional injuries (4%)
Neuropsychiatric disorders (2%)
Total deaths: 4.3 million Noncommunicable conditions: 50% Communicable diseases*: 39% Injuries: 11%
www.who.int/healthinfo/global_burden_disease/estimates_regional/en/index.html
* Including maternal and perinatal conditions and nutritional deficiencies
Diabetes (2%)
Noncommunicable DiseasesMagnitude in the Middle East



Epidemiologic transition
Current & Projected Burden of Diseases
China
India
Rest of Asia
(Murray & Lopez, 1990)

Noncommunicable Diseases & InjuriesProjected global deaths (2030)

Cancers
Stroke
Road trafficaccidents
HIV/AIDS
TB
Malaria
Acute respiratoryinfections
Ischaemic heart disease
Perinatal
www.who.int/healthinfo/global_burden_disease/2004_report_update/en/index.html

Research for prevention and control of Non-communicable Diseases

Globally:- NCDS currently cause over 60% of all deaths 80% of these deaths occur in developing countries Around a quarter of these deaths occur in people under 60 years of age.


Injuries
Cause 10% of all deaths and 16% of all disability Road traffic crashes alone are the leading cause of death for young people aged 10-24 years

Problems in Etiologic Investigation of Chronic Non-Communicable Diseases (NCDs):

1.Absence of a known agent 2.Multifactoral nature of etiology 3.Long latency period 4.Indefinite onset 5.Differential effect of factors on incidence and course of the disease


Prevention of NCDs received little attention by policy makers, medical professionals, and general public because:
The extent is less sufficiently examined Long delay between cause and effect

Infectious Diseases

Non-Infectious Diseases
a necessary agent Specific agent-disease relationship Causes are relatively well understood Short incubation period
No single necessary agent One-to-one correspondence between agent and disease very rare Causes unknown, intervention usually based on risk factors Long latency period

Infectious Diseases

Non-Infectious Diseases
Single exposure usually sufficient Usually produce acute disease Acquired immunity possible Dx based on tests specific to disease agent
May require multiple exposure to same or multiple agents Most often produce chronic disease Acquired immune unlikely Dx often dependent on nonspecific symptoms or test



PRIMARY Prevention is possible for most NCDs due to the following facts:
1.Large population differences in incidence and mortality of NCDs 2.Dynamic national trends in incidence and mortality rates of most NCDs 3.Rapid changes in risk of many NCDs among migrant population 4,Positive results of intervention trials 5.Identification of modifiable risk factors of many NCDs

CONTROL OF NCDs

A. PRIMARY PREVENTION - removal of agent from environment or minimizing the amount of agent present - Protection of the susceptible host from exposure B. SECONDARY PREVENTION - screening tests C. TERTIARY PREVENTION - Prevention of complications

NCDs and Injuries Magnitude

Four major NCDs:Cardiovascular diseasesDiabetesCancersChronic respiratory diseasesFour shared modifiable risk factors:Tobacco useUnhealthy dietPhysical inactivityHarmful use of alcohol60% of deaths globally – 70% if injuries are included -80% in developing countries40-50% are prematureMagnitude has a major socio-economic impact on developing countries

NCDs and injuries are preventable We know what works We have cost-effective interventions: Tobacco control interventions Measures to improve healthy dietary and physical activity patterns Early detection and effective treatment of cancer Treatment of hypertension, diabetes Treatment of heart disease and stroke Intersectoral injury prevention measures

Thanks