This document discusses the concept of multifactorial causation in diseases. It explains that modern diseases like cancer, heart disease, and mental illness cannot be fully explained by a single cause or prevented through measures like immunization. These diseases are caused by multiple interacting factors, including lifestyle, behavioral, environmental, and genetic influences. Obesity is provided as a key example of a multifactorial condition influenced by factors like urbanization, food availability, physical activity levels, and acquired influences exceeding genetic factors. Preventing such diseases requires addressing any of the various causal factors.

1. Multifactorial
causation
Presented by : Kumar Nyaupane

2. Introduction
• As a result of advances in public health,
chemotherapy ,antibiotics and vector control the
communicable diseases begin to decline – only to
be replaced by new types of diseases so called
modern disease of civilization eg. lung cancer,
CHD, bronchitis, COPD , mental illness.
• These disease could not be explained on the basis
of germ theory of disease nor prevented by
immunization, isolation , sanitation.

3. Contd…
• Multiple factors leads to the disease
• Common in non communicable disease
• Alternative causal factors each acting
independently
• Example :
• In lung cancer , air pollution , smoking ,
hereditary can produce lung cancer
independently.

4. Contd…
• The realization began to dawn that the single
cause idea was an oversimplification and
there are other factors in the etiology of
diseases – social, economic, cultural, genetic
• Example tuberculosis is not merely due
tubercle bacilli, factors such as poverty ,
overcrowding and malnutrition contribute to
its occurrence .

5. Contd…
• It is well known that CHD, cancer etc are due to
multiple factors example, excess fat intake,
smoking, alcohol , obesity, lack of exercise
• Behavior, lifestyle, environmental causes,
ecological elements, physical factors must be
taken into account while describing disease
causation.
• The term agent is replaced by causative factors
which implies the need to identify multiple
causes or factors in advanced model of triangle of
epidemiology.

6. Multifactorial causation in disease
prevention
• Example :
• Obesity threatens to become the foremost
cause of chronic disease in the world . being
obese can induce multiple metabolic
abnormalities that contribute to
cardiovascular disease , diabetes mellitus and
other chronic disorders .
• Unfortunately prevalence of obesity is
increasing in the world.

7. Contd…
• Reason to rising prevalence include urbanization
of worlds population , increased availability of
food supplies and reduction in physical activity.
• Although severe obesity has received much
attention in the clinical setting , most obesity in
general public is moderate .
• Moderate obesity is undoubtedly multifactorial in
origin and acquired influences probably exceed
genetic factors in its causation.

8. Contd….
• Therefore the prevention includes the change in
any of the causal factor .
• Example :
• Lifestyle habits (Sleeping , Diet)
• Social factors(poverty , less healthier foods)
• Alcohol and smoking
• Medical factors (age , cushings syndrome ,
hypothyroidism , medications , psychological
issues)