Epidemiology help Given the Prevalence and Incidence rates p

Epidemiology help!!

Given the Prevalence and Incidence rates per 100,000, compute the average duration, in years of the three neurological conditions listed. As we know, Incidence and Prevalence are positively related. Incidence of coronary heart disease increases with age. However, it was observed that the prevalence of coronary heart disease decreases after age 70. What is the most probable explanation for the divergence of these rates? A small city in North Carolina had a population of 100,000 people (45,000 males and 55,000 females) during 2016, and 1, 100 people died that year (625 males and 475 females). There were 60 cases (35 males and 25 females) of lung cancer during the year, of whom, 40 died (25 males and 15 females). For 2016, Compute (per 1000, or other as appropriate): Crude mortality rate Sex-specific mortality rates (M & F) Cause-specific mortality rate for lung cancer Case fatality rate for lung cancer PMR for lung cancer

Solution

2. Average duration = Prevalence/ Incidence

Epilepsy = 374/100000 persons / 10.8/100000 persons

= 34.62 ~ 35 years

Multiple Sclerosis = 55/100000 persons / 7/100000 persons = 7.85 ~ 7 years

Parkinson\'s Disease = 155 /100000 persons / 12/100000 persons

= 12.91 ~ 13 years

3. Though prevalence and incidence are positively related, prevalence is also influenced by the average duration of the disease. As mentioned in the question, the rate of incidence of CHD increases with age. With regard to the duration of disease, If it is incident in older people, it eventually leads to increased death rate of old people and thus lowering the prevalence of the disease.

4. a. Crude mortality rate = No. of deaths/Population affected = 1100/ 100000 = 0.011 x 1000 = 11 per every 100000 individual

b. Sex- specific mortality rate

Male = No. of male deaths/ Population =625/100000 = 0.00625

Female = No. of female deaths/ Population = 475/100000 = 0.00475

c. Cause specific mortality rate = No. of deaths due to the cause/Population = 40/100000 = 0.0004 x 10000 = 4 per every 100000 individual

d. Case fatality rate of lung cancer = No. of deaths due to lung cancer/ Population with lung cancer = 40/60 x 100= 0.666 x 100 = 66.66

e. PMR for lung cancer = No. of deaths due to lung cancer / Total no. of deaths x 100 = 40/1100 = 3.636