Question

They found a total of 59 patients. Fill in the attack rate per million[SL1] and the RR by characteristic – use the category of that characteristic marked with a * as the reference group (may differ from original paper) (6pts)

Addressed in q 1 on Exercise 3 Prep Work

Characteristic #cases(%) NYC population attack rate** RR by

per million pop. characteristic

Age(yr)

0–19 * 2 (3) 2,324,081 0.9 1.0

20–29 1 (2) 1,553,981 0.6 ____

30–39 3 (5) 1,549,111 1.9 ____

40–49 1 (2) 1,177,190 1.7 ____

50–59 9 (15) 867,331 10.4 ____

60–69 13 (22) 814,838 16.0 ____

70–79 18 (31) 534,785 33.7 ____

»80 12 (20) 281,054 42.7 49.615

Age category (yr)

»50 * 52 (88) 2,498,008 20.8 ____

<50 7 (12) 6,604,363 1.06 1.0

Sex

Male* 31 (53) 4,289,988 7.2 ____

Female 28 (47) 4,812,383 5.8 1.0

Race

White* 41 (69) 5,983,901 6.9 ____

Nonwhite 9 (15) 3,118,470 2.9 1.0

Unknown 9 (15) ------ n/a n/a

Borough or county of residence

New York City

Brooklyn (Kings) * 3 (5) 2,300,664 1.3 ___

Bronx 9 (15) 1,203,789 7.5 ____

Manhattan 1 (2) 1,487,536 0.7 ____

Queens 32 (54)§ 1,951,599 16.4 ____

Staten Island 0 379,999 0 ____

New York State

(just outside the city) 14 2,162,214 we will ignore this risk group for this exercise

*Population figures are from the 1990 U.S. Census. †CI denotes confidence interval. . §This group includes a Canadian tourist who became ill after visiting relatives in Queens

** Actually, the authors called it "rate of infection" in this column but still attack rates in the heading. That is somewhat misleading since the data has no unit of time (not a rate) and this only counts cases- not actual infections. These are accepted limitations of what is generally called "attack rate" in an investigation

Calculate the overall attack rate [SL2] (1 pt.) Addressed on Exercise 3 Prep Work

Describe 2 of the patterns you can see from this data. (2pts)

".

Answer 1

Answer and Explanation:

To calculate the overall attack rate, we need to determine the number of cases per million population.

Given:

Total number of cases = 59

NYC population = 8,008,278

Step 1: Calculate the overall attack rate.

Attack rate = (number of cases / NYC population) * 1,000,000

Attack rate = (59 / 8,008,278) * 1,000,000 ≈ 7,367

The overall attack rate is approximately 7,367 per million population.

From the data provided, we can observe two patterns:

Pattern 1: Age-Related Risk

- The attack rate increases with age. The highest attack rates are observed in the older age groups (60-69 and 70-79), while the lowest attack rate is in the youngest age group (0-19).

- This pattern suggests that older individuals are more susceptible to the disease compared to younger individuals.

Pattern 2: Gender Difference

- The attack rate for males is higher than that for females. The attack rate for males is 7.2 per million population, while for females, it is 5.8 per million population.

- This pattern suggests that males may have a higher risk of contracting the disease compared to females.

These patterns provide insights into the distribution of the disease across different characteristics, highlighting the varying risks based on age and gender.