Cohort studies are the analytical design of observational studies that are epidemiologically used to identify and quantify the relationship between exposure and outcome. Due to the longitudinal design, cohort studies have several advantages over other types of observational studies. The purpose of this chapter is to cover the various characteristics of prospective cohort studies. This chapter is divided into three main sections. In the first we introduce the concept and ranking of cohort studies, as well as the advantages and disadvantages. In the second we focus on the design of cohort studies, mainly its prospective aspect, and the distinguishing features from the retrospective type. The section also covers the essential characteristics of a cohort study design and its varied applications in medical research. In the third we go over examples of prospective studies in the medical field. For each, an overview of the study design is given, along with a random selection of study findings/impact, strengths and weaknesses.

Cystic fibrosis (CF) is a genetic autosomal recessive disease that involves multiple systems. Both life quality and expectation are affected by the debilitating multi-system involvement of the disease which includes pulmonary, gastrointestinal, reproductive, and endocrine symptoms. Very few studies have covered the epidemiological aspects of the disease among Arab countries. To systematically review the available epidemiological literature on cystic fibrosis in order to describe the epidemiological state of this disease in the Arab world, this review used PubMed to search for relevant articles related to patients with cystic fibrosis, with no restriction on gender or age. Google scholar and the snowballing technique were used to locate further articles. A total of 17 articles met the inclusion criteria for this review. These articles were from Bahrain, Egypt, Jordan, Kuwait, Morocco, Oman, Saudi Arabia, Tunisia, and the United Arab Emirates. The articles scored 1.5–6.5 out of 8 on the quality assessment. The epidemiological data reported varied based on country and type of study. The establishment of CF registries is definitely a priority in the region, as well as the need for more research involving CF patients particularly those involving the epidemiological and clinical characteristics of these patients.

This cross‐sectional study aims to utilize the Global Asthma Network (GAN) questionnaires to estimate the prevalence of asthma, allergic rhinitis, and eczema among children in Qatar. The study population was comprised of children ages 6–7 and 13–14 years, along with their parents or guardians. The English and Arabic versions of the GAN questionnaires were used to collect data for this study. A total of 2646 participants were recruited (1210 in the 6–7 years age group and 1436 in the 13–14 years age group), in addition to a total of 3831 parents or guardians. The overall prevalence of diagnosed asthma, lifetime allergic rhinitis, and diagnosed eczema in our study sample were as follows: 34.6%, 30.9%, and 37.4%, respectively. The current study showed an increased prevalence rate of asthma and eczema comparing to previous local estimates. These rates were higher in some cases or comparable in other cases to those found elsewhere. It is recommended that future research focus on studying the various factors contributing to the cases of asthma, allergic rhinitis, and eczema in Qatar. The reporting of this study conforms with the STROBE statement.

No abstract

No abstract