Epidemiology module of practical skills for mbbs student

Age group (Years)	No. of women (A)
No. of live births (B)
15-19	25000	800
20-24	20000	2400
25-29	19000	2000
30-34	16000	1500
35-39	14000	120
40-44	6000	10
Total	100000	6830

Computation of age specific fertility rate:

Step I: C=B/AX1000
For age 15-19 years = 800/25000x1000=32.00

For age 20-24 years = 2400/20000x1000=120.00

For age 25-29 years = 2000/19000x1000=105.26

For age 30-34 years = 1500/16000x1000=93.75

For age 35-39 years = 120/14000x1000=8.57

For age 40-44 years = 10/6000x1000 = 1.67

Step II: Total Births=CX5

Exact age (years)	SFRx5 (SFRxclass interval)	Total births per 1000 females aged 15 to 44 by stated ages
15-19	32x5=160	160
20-24	120x5=600	760
25-29	105.26x5=526.30	1286.30
30-34	93.75x5=468.75	1755.05
35-39	08.57x5=42.85	1797.90
40-44	01.67x5=8.35	1806.25

Total fertility rate (TFR) = sum of S.F.R./1000

= 1806.25/1000

= 1.8

3. 
   Net Reproduction Rate (NRR): NRR is defined as the number of daughters a new born girl will bear during her life time assuming fixed age specific fertility and mortality rate. NRR is a demographic indicator. NRR of 1 is equivalent to attaining approximately the 2-child norm. If the NRR is less than 1 then the reproductive performance of the population is said to be below replacement level.
   

The Demographers are of the view that the goal of NRR 1 can be achieved only if effective couple protection rate is above 60%.
Example:

Age group	Female population	Female births	Specific fertility rate per women (S.F.R.)	Survival rate (S)	S.F.R. x S
15-19	1600000	19000	0.0119	0.921	0.0110
20-24	10,00000	70200	0.0702	0.901	0.0633
25-29	16,8500	90600	0.0538	0.885	0.0476
30-34	17,30000	62400	0.0361	0.862	0.0311
35-39	1,72000	32500	0.0188	0.850	0.0160
40-44	16,20000	11000	0.0068	0.832	0.0057
Total					0.1747

NRR=sum (S.F.R. x S) x class interval5

= 0.1747 x 5

= 0.8735

4. 
   MEASUREMENTS OF DISABILITY
   

The sequence of events leading to disability and handicap has been stated as follows:

Disease – Impairment – Disability – Handicap

Impairment: Any loss or abnormality of psychological, physiological or anatomical structure or function, e.g. loss of foot, defective vision or mental retardation.

Disability: Any restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being. Disability may be physical, mental and social.

Handicap: A disadvantage for a given individual resulting from impairment or a disability that limits or prevents the fulfillment of a role that is normal (depending on age, sex and social and cultural factors) for that individual.

Illustration

Poliomyelitis - Disease

Paralysis of limb - Impairment.

Inability to walk -Disability

Unemployment - Handicap

Types

(A) Physical, (B) Mental, (C) Social

A. Physical disability: e.g., blindness, lameness, deafness, etc.

B. Mental disability: e.g. psychosis, mental retardation,

C. Social disability: orphan, destitute, etc.
Disability Adjusted Life Years (DALYs): It measures the healthy life years lost because of premature mortality. Calculated as difference between actual age at death and life expectancy at that age and disability resulted from diseases. For calculating DALYs criteria considered are mobility, anxiety or depression, self care, pain, cognitive function and carrying out normal activity.

There is huge variation in per person loss of DALYs across regions mainly because of differences in premature mortality. Regional differences in loss of DALYs as a result of disability are much smaller. About 1.36 billion DALYs were lost in 1990, which is equivalent to 42 million deaths of newborn or 80 million deaths at the age of 50. Premature deaths were responsible for 66% of all DALYs lost and disabilities for 34%. In India 50.5% DALYs were lost because of communicable diseases (TB, STD & HIV, Diarrhoea, VPDs, Malaria, worm infestation, respiratory infections, maternal causes, perinatal causes etc.) and 40.4% due to non-communicable diseases (Cancers, nutritional deficiencies, psychiatric diseases, cerebrum-vascular diseases, ischemic heart diseases, etc. ) and 9.1% due to injuries (Motor vehicle, intentional and others).

After knowing the practical implication of basic principles of epidemiology we have to move on the other very important aspect of data management . For this we need to know the basic of data as –