Study Background: This study compared the effects of a new inhaled asthma drug (Inhaler X) to other inhaled treatments among a group of adult asthma patients. Asthma patients who initiated a new prescription for an inhaled asthma drug between 10/1/10 and 12/31/10 were eligible to be included in the study. These individuals were categorized according to whether they initiated Inhaler X or another inhaled asthma drug. A total of 650 eligible individuals with asthma were considered new users of inhaled asthma drugs and were willing to be enrolled and undergo a medical examination on January 1, 2011. At enrollment, participants also answered an extensive questionnaire on social, demographic, diet, and lifestyle characteristics.

1. Using the data from Table 1, compute the percentage of study participants with new use of Inhaler X in the 90 days before enrollment among the eligible participants with asthma. Is this a prevalence proportion or an incidence proportion
2. In Table 1, the investigators recorded the number of patients with each demographic characteristic, stratified by whether or not they were new users of Inhaler X or another inhaled asthma drug. Given the number of patients with each characteristic in Table 1, calculate the percent of each age and sex category for all study participants, those who are new users of Inhaler X, and those who are users of other inhaled asthma drugs (categories in blue boxes). Round to one decimal place.
3. Is the percent of individuals with each demographic variable an incident or prevalent value?

Table 1. Partial demographic characteristics for a cohort of patients attending a network clinic on January 1, 2011 by use of Inhaler X or another inhaled drug (n=650).

Characteristic	Total N=650		Inhaler X n=176		Other Inhaled Drug n=474
No.	%		No.	%		No.	%
Age Group (yrs)
18-29	140			33			109
30-39	122			27			96
40-49	115			34			83
50-59	123			40			81
60-70	150			42			105
Sex
Male	321			86			234
Female	329			90			240