To determine the prevalence and routes of transmission of hepatitis C virus (HCV) infection in Hafizabad, Pakistan, we collected sera in 1993 from a geographically based random sample of residents, and in 1994 identified 15 HCV-infected individuals (cases) and 67 age and sex matched uninfected individuals (controls). Initially we approached 504 households, and collected serum from a randomly selected household member in 309 (64%). Twenty persons (6·5%) had anti-HCV antibody; 31% percent had hepatitis B core antibodies, and 4·3% had hepatitis B surface antigen. In the case-control study, persons who received more therapeutic injections (categorized as averaging 1, 2–4, 5–9 or >10 injections per year in the previous 10 years) were more likely to be infected with HCV (odds ratio 0, 1·5, 2·5 and 6·9 respectively, P=0·008) compared to persons averaging 0 injections per year. Efforts to limit therapeutic injections to only those that are medically indicated and that use sterile equipment are essential in order to prevent transmission of HCV.

Introduction: The purpose of this article is to provide a general understanding of the concepts of sampling as applied to health-related research. Sample Size Estimation: It is important to select a representative sample in quantitative research in order to be able to generalize the results to the target population. The sample should be of the required sample size and must be selected using an appropriate probability sampling technique. There are many hidden biases which can adversely affect the outcome of the study. Important factors to consider for estimating the sample size include the size of the study population, confidence level, expected proportion of the outcome variable (for categorical variables)/standard deviation of the outcome variable (for numerical variables), and the required precision (margin of accuracy) from the study. The more the precision required, the greater is the required sample size. Sampling Techniques: The probability sampling techniques applied for health related research include simple random sampling, systematic random sampling, stratified random sampling, cluster sampling, and multistage sampling. These are more recommended than the nonprobability sampling techniques, because the results of the study can be generalized to the target population

This article describes the importance of selecting the appropriate epidemiological study design for a given study question. It provides an explanation to the different terms used in describing study designs with regards to observational versus interventional and descriptive versus analytical types of study designs. This article focuses on the description of the different types of descriptive study designs, that is, case report, case series, correlational, and cross-sectional study designs. The requirements for selecting these study designs are discussed along with the advantages and disadvantages of each study design. The descriptive studies are similar in the context that they are based on a single sample with no comparative group within the study design. Their basic purpose is to describe the characteristics of the sample with regards to the characteristics that are present and so are useful in generating a hypothesis. The absence of a comparative group is the main limitation of the descriptive studies, and this is the reason they cannot be used to determine an association by testing a hypothesis showing a relationship between a risk factor and disease. The analytical study designs will be discussed in the next article in this series.

Patients with primary childhood nephrotic syndrome (PCNS) develop alterations in their cellular and humoral immunity that predisposes them to the development of infection, and lead them to have frequent relapses. Also, infection could be significantly enhanced by immunosuppressive agents. This study aims to estimate the immunosuppressive burden, rate of infection and identify possible risk factors in PCNS requiring hospitalization. A cross-sectional study of hospitalized children≤14years of age diagnosed with PCNS in King Abdul-Aziz Medical City, Riyadh from January 2003 to December 2013. Out of 111 patients admitted with PCNS, 84 (76%) had both minor and major types of infection. Upper respiratory tract infection (URTI) was the most predominant type (n=44, 52%). Among the major types of infection, urinary tract infection (UTI) was the most common infection (n=21, 25%) followed by pneumonia (n=17, 20%) then cellulitis (n=6, 6%). Infection in children who received a higher annual cumulative dose of steroids (CDS) strikingly had a higher rate of infection in comparison to those who received lower CDS (p<0.01). Moreover, those who received primary and secondary immunosuppressant's had 100% infection rate. About half of infection encountered by PCNS patients were URTI followed by UTI and pneumonia. Higher annual CDS, combination of primary and secondary immunosuppressants were the highest independent risk factors for infection. Among the infection, URTI was considered as the predominant entity whereas among the major infection, UTI was predominant followed by pneumonia then cellulitis.

Upper respiratory tract infection (URTI) is considered to be the most common reason for children's visits to emergency departments or outpatient clinics. The misuse and overuse of antibiotics are currently major public health problems worldwide. This study aimed to assess Saudi parents' knowledge, attitude, and practice (KAP) regarding the use of antibiotics in URTIs in children. This cross-sectional study was conducted in Saudi Arabia using a previously validated questionnaire, which was distributed using Twitter. A total of 385 individuals completed the questionnaire. For the majority of the participants (77%), physicians were the primary source of information regarding the use of antibiotics. Forty-four percent of parents agreed that most URTIs are caused by viruses, and 81% were aware that inappropriate use of antibiotics leads to the development of antibiotic resistance. Fever was the primary symptom (27%) that led parents to ask for prescriptions for antibiotics. Although women had a higher attitude score (p=0.01), there was no difference between genders regarding knowledge and practice. Older participants (41 years or more) had a lower attitude score (p=0.02). Furthermore, participants with five children or more had lower attitude and practice scores (p=0.006, 0.04, respectively). Participants who lived in large cities had greater knowledge compared to the inhabitants of small cities (p=0.01). In conclusion, the findings of this study demonstrated that most of the participants were educated but lacked knowledge regarding antibiotic use in URTIs in children. This lack of knowledge led to inappropriate attitude and practice. Thus, launching public educational campaigns and encouraging physicians to educate parents regarding the proper use of antibiotics are recommended.

Purpose: Vitiligo is a skin condition characterized by patchy depigmentation in the skin, affecting not just the physical well-being of patients, but also the mental, emotional, and social aspects of their lives. Social media provides a platform where patients can interact and share experiences, and for physicians and experts to disseminate knowledge on the disease. This study aimed to evaluate the accuracy and overall quality of vitiligo-related content on YouTube. Methods: Thirty videos were screened by relevance according to the inclusion criteria. Videos were categorized as either healthcare or non-healthcare sources, and viewer engagement ratio was calculated for each. Three independent vitiligo experts rated the content using the following assessment tools: DISCERN, Accuracy in Digital-health Instrument (ANDI), and Global Quality Scale (GQS). Lastly, Cronbach’s alpha was used to estimate the inter-rater reliability and consistency. Results: Most of the screened videos came from health-care sources (57%). Non-healthcare sources achieved a slightly higher viewer engagement ratio, although the difference is not statistically significant (p = 0.23). DISCERN score was low overall in most videos. However, DISCERN score was higher for health-care sources as compared to non-healthcare sources (30.5 ± 9.4 vs 22.7 ± 4,2, p = 0.009). Scores of ANDI and GQS were higher for health-care sources but not statistically significant. There was a good internal consistency in DISCERN rating among the evaluators (0.86). Conclusion: Our study shows a low overall accuracy and quality of YouTube videos on vitiligo. It is recommended that health-care sources improve their information material in terms of quality and viewer engagement, as very little can be done to prevent non-healthcare sources in publishing their own videos. Efforts in educating the public on making distinction between evidence and non-evidence-based claims should also be taken.