Epidemiology of Non-Communicable Diseases

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Epidemiology of Non-Communicable Diseases

• Dr. REKHA DUTT

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• Chronic diseases
• definitions
• An impairment of bodily structure or function
  that necessitates a modification of the patients
  normal life, and has persisted over an extended
  period of time.
• Diseases comprising all impairments or deviations
  from normal, which have one or more of the
  following characteristics
• Are permanent
• Leave residual disability
• Are caused by non reversible pathological
  alterations
• Require special training of the patient for
  rehabilitation
• May be expected to require a long period of
  supervision, observation or care

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NON- COMMUNICABLE DISEASES INCLUDE

• Cardiovascular ( hypertension, coronary artery
  disease, stroke )
• Renal (nephritis, nephrotic syndrome)
• Nervous and mental ( mania, depression)
• Musculoskeletal ( arthritis)
• Respiratory (asthma, emphysema, bronchitis)
• Cancer
• Diabetes
• Obesity
• Blindness
• Degenerative disorders
• Accidents

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• The problem
• Cancer 2.5 million cancer cases in the country
  and will double in next 2 decades
• Coronary heart disease (CHD) data is inadequate
  in urban Kerala it is 14
• ( 17 in men and 10 in women)
• Hypertension 10 urban and 5 rural
• Diabetes a recent study carried out in 6 cities
  in India showed an age standardized prevalence of
  diabetes and impaired glucose intolerance in 12
  and 14 respectively.
• Developing countries are now warned to take
  appropriate steps to avoid the epidemics of NCD
  likely to come with socioeconomic and health
  development.

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• Rise in life expectancy and increasing number of
  senior citizens
• Changing lifestyles faulty diet, alcohol intake,
  sedentary life, obesity, stress
• Tobacco
• Exposure to environmental risk factors- air
  pollution
• Increasing population

causes
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Gaps in the natural history of NCD

• Absence of known agent in most of NCD the cause
  is not known.
• Multifactorial causation in absence of causative
  agents, risk factors are studied

• An attribute or exposure that is significantly
  associated with development of disease.
• If determinant is modified by intervention, it
  reduces possibility of occurrence of disease.
• Risk factors can be causative, contributory or
  predictive.
• They can be modifiable or non-modifiable
• They can be individual or community risk factors
• Epidemiological studies are needed to identify
  risk factors
• At-risk approach, at-risk groups, risk factors
  with diseases

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Gaps in the natural history of NCD

• Web of causation
• Changes in life style stress
• Abundance of food lack of physical
  activity smoking emotional disturbance
• aging
• Obesity hypertension
• Hyperlipidemia thrombotic tendency
• changes artery walls
• Coronary arthrosclerosis coronary occlusion

Myocardial infarction
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Gaps in the natural history of NCD

• Long latent period it is the period between the
  first exposure to suspected cause and the
  eventual development of disease. This makes it
  difficult to link suspected causes with outcomes.
• Indefinite onset Most (NCD) are slow in onset
  and development. Distinction between diseased and
  non diseased may be difficult to establish.

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Prevention of NCD

• Levels of prevention
• Primordial
• Primary
• Secondary
• Tertiary
• Primordial prevention- Prevention of the
  emergence or development of risk factors in
  countries or population groups in which they have
  not yet appeared. Efforts are directed towards
  discouraging children from adopting harmful life
  styles.
• Primary prevention- Action taken prior to the
  onset of disease which removes the possibility
  that the disease will ever occur. Can be divided
  into population high risk strategy.

For healthy people
For unhealthy people
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Prevention of NCD
Primary prevention

• Interventions
• Health promotion
• Specific protection
• Adequate nutrition
• Safe water and sanitation
• Secondary prevention-Action which halts the
  progress of the disease at its incipient stage
  and prevents complications. Mostly curative.
  Disadvantage - patient has already suffered
  mental physical anguish community to loss of
  production. Often more expensive less effective.
  Intervention EARLY DIAGNOSIS AND TREATMENT
• Tertiary prevention- defined as all measures
  available to reduce impairments disabilities,
  minimize suffering due to departure from good
  health promote patients adjustment to
  irremediable conditions.Intervention DISABILITY
  LIMITATION AND REHABILITATION

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Response to NCD

• Centrally sponsored schemes
• National iodine deficiency disorders control
  programme
• National programme for control of blindness
• The national cancer control program
• Pilot projects
• National mental health, diabetes control,
  cardiovascular diseases and prevention of
  deafness, oral health programme

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Future

• Efforts will be made to improve preventive,
  promotive, curative and rehabilitative services
  for NCD.The major thrust will be on
• Well structured information education and
  communication for primary and secondary
  prevention of disease.
• Reorientation and skill up gradation of health
  providers
• Establishments of referral linkages between
  primary, secondary and tertiary institutions.
• Production and provisions of drugs.
• Development of institutions for rehabilitation of
  disabled persons due to NCD .
• Development of hospitals for terminally ill
  patients, who can not have home based care.
• Creation of epidemiological data base on NCD .

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Causation in epidemiology

• Cause is an event, circumstance, condition, risk
  factor, exposure, characteristic or a combination
  of these factors, which results in producing the
  disease.
• Necessary cause Vibrio cholerae is necessary for
  Cholera.
• Sufficient cause are factors and conditions
  ,which are other than the etiological cause of
  disease.
• In sanitary conditions, water conditions,
  adequate dose of vibrio cholerae,host immunity.

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Association and causation

• Association may be defined as the concurrence of
  two variables more often than would be expected
  by chance.
• It does not necessarily imply a causal
  relationship.
• Correlation indicates the degree of association
  between two characteristics.
• The correlation coefficients range from -1.0 to
  1.0

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• 1. Spurious association
• When an observed association between a disease
  and suspected factor is not real.
• Direct (causal)
• One to one relationship
• Germ theory of disease
• Necessary cause
• Sufficient cause
• Multifactorial causation

• 3.Indirect association
• It is statistical association between a variable
  and a disease due to presence of another factor
  known or unknown, that is common to both the
  variable and disease. This common factor is
  confounding factor.
• altitude
• Iodine deficiency
• endemic
• goiter

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Criteria for causality
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• Temporal association the cause must precede the
  effect.
• Strength of association
• Larger the relative risk greater the likely hood
  of causal relation
• Dose response and duration response relationship
• Specificity of association one to one
  relationship between cause and effect.
• It is difficult in chronic diseases.
• lung cancer
• CAD
• Cigarette smoking ca cervix
• 
  bronchitis

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• Consistency of association
• When results are replicated when studied in
  different settings and by different methods.
• Biological plausibility
• Association agrees with current understanding of
  the response of cells, tissues, organs and system
  to stimuli.
• Food intake and cancer are correlated. The
  positive association of intestine and rectal
  carcinoma is logical whereas positive association
  of food and Ca. skin makes no biological sense.
• Coherence of association
• Rising consumption of tobacco in form of
  cigarettes and rising incidence of lung Ca.
• Fall in RR of lung Ca when smoking is stopped.

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thank you