Question

We carried out a community study in Singapore to determine the prevalence of specific central nervous system (CNS) symptoms among hand-held cellular telephone (HP) users compared to nonusers and to study the association of risk factors and CNS symptoms among HP users. A total of 808 men and women between 12 and 70 years of age, who lived in one community, were selected using one-stage cluster random sampling and responses to a structured questionnaire. The prevalence of HP users was 44.8%. Headache was the most prevalent symptom among HP users compared to non-HP users, with prevalence rate ratio of 1.31 [95% confidence interval, 1.00-1.70]. There is a significant increase in the prevalence of headache with increasing duration of usage (in minutes per day). The use of HPs is not associated with a significant increase of CNS symptoms other than headache.

Note: the prevalence of headache among HP users was 60.3%.

Based on this abstract, indicate the following:

1. The study design:    
2. The exposure/risk factor:
3. The disease/outcome(s):

Answer 1

Study design	Meaning
Cross sectional study	It is a type of observational study design in which cause and effect relationship is investigated in a population or its representative subset at the same point in time. the above study used one -stage cluster random sampling to collect data from representative subset.
The exposure/risk factor usage of hand held cellular telephone (HP)	A factor that is related to the outcome of interest is called exposure.
The disease/outcome(s) Prevalence of headache	Outcome(disease) is the effect due to a risk factor/ exposure. The main measure in this type of research design is the prevalence of outcome.