This new edition of Ann Bowling's well-known and highly respected text has been thoroughly revised and updated to reflect key methodological developments in health research. It is a comprehensive, easy to read, guide to the range of methods used to study and evaluate health and health services. It describes the concepts and methods used by the main disciplines involved in health research, including: demography, epidemiology, health economics, psychology and sociology.The research methods described cover the assessment of health needs, morbidity and mortality trends and rates, costing health services, sampling for survey research, cross-sectional and longitudinal survey design, experimental methods and techniques of group assignment, questionnaire design, interviewing techniques, coding and analysis of quantitative data, methods and analysis of qualitative observational studies, and types of unstructured interviewing. With new material on topics such as cluster randomization, utility analyses, patients' preferences, and perception of risk, the text is aimed at students and researchers of health and health services. It has also been designed for health professionals and policy makers who have responsibility for applying research findings in practice, and who need to know how to judge the value of that research.

Research Methods in Health. Investigating health and health services

Free radicals and oxidants play a dual role as both toxic and beneficial compounds, since they can be either harmful or helpful to the body. They are produced either from normal cell metabolisms in situ or from external sources (pollution, cigarette smoke, radiation, medication). When an overload of free radicals cannot gradually be destroyed, their accumulation in the body generates a phenomenon called oxidative stress. This process plays a major part in the development of chronic and degenerative illness such as cancer, autoimmune disorders, aging, cataract, rheumatoid arthritis, cardiovascular and neurodegenerative diseases. The human body has several mechanisms to counteract oxidative stress by producing antioxidants, which are either naturally produced in situ, or externally supplied through foods and/or supplements. This mini-review deals with the taxonomy, the mechanisms of formation and catabolism of the free radicals, it examines their beneficial and deleterious effects on cellular activities, it highlights the potential role of the antioxidants in preventing and repairing damages caused by oxidative stress, and it discusses the antioxidant supplementation in health maintenance.

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Free Radicals, Antioxidants in Disease and Health

eMedicine创建于1996年，由近万名临床医师作为作者或编辑参与此临床医学知识库的建设，其中编辑均是来自美国哈佛、耶鲁、斯坦福、芝加哥、德克萨斯、加州大学等各分校医学院的教授或副教授。

eMedicine

Description Update of the 2009 US Preventive Services Task Force (USPSTF) recommendation on screening for depression in adults. Methods The USPSTF reviewed the evidence on the benefits and harms of screening for depression in adult populations, including older adults and pregnant and postpartum women; the accuracy of depression screening instruments; and the benefits and harms of depression treatment in these populations. Population This recommendation applies to adults 18 years and older. Recommendation The USPSTF recommends screening for depression in the general adult population, including pregnant and postpartum women. Screening should be implemented with adequate systems in place to ensure accurate diagnosis, effective treatment, and appropriate follow-up. (B recommendation)

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Screening for Depression in Adults: US Preventive Services Task Force Recommendation Statement.

Oxidative stress has been proven to be related to the onset of a large number of health disorders. This chemical stress is triggered by an excess of free radicals, which are generated in cells because of a wide variety of exogenous and endogenous processes. Therefore, finding strategies for efficiently detoxifying free radicals has become a subject of a great interest, from both an academic and practical points of view. Melatonin is a ubiquitous and versatile molecule that exhibits most of the desirable characteristics of a good antioxidant. The amount of data gathered so far regarding the protective action of melatonin against oxidative stress is overwhelming. However, rather little is known concerning the chemical mechanisms involved in this activity. This review summarizes the current progress in understanding the physicochemical insights related to the free radical-scavenging activity of melatonin. Thus far, there is a general agreement that electron transfer and hydrogen transfer are the main mechanisms involved in the reactions of melatonin with free radicals. However, the relative importance of other mechanisms is also analyzed. The chemical nature of the reacting free radical also has an influence on the relative importance of the different mechanisms of these reactions. Therefore, this point has also been discussed in detail in the current review. Based on the available data, it is concluded that melatonin efficiently protects against oxidative stress by a variety of mechanisms. Moreover, it is proposed that even though it has been referred to as the chemical expression of darkness, perhaps it could also be referred to as the chemical light of health.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-079X.2011.00916.x

Melatonin as a natural ally against oxidative stress: a physicochemical examination

This study was conducted to determine a possible relationship between regular cell phone use and different human semen attributes. The history-taking of men in our university clinic was supplemente...

https://www.tandfonline.com/doi/pdf/10.1080/014850190924520

Is there a relationship between cell phone use and semen quality

The aim of this study was to examine the relationship of semen parameters, sexual function-related hormones and waist/hip ratio. Eighty-one selected patients presenting with infertility were examined. Weight, height, waist circumference and hip circumference were measured, and reproduction-related hormone levels were determined. Semen was analysed by conventional methods. Semen volume, sperm concentration, motility, total sperm count, total motile sperm cell number, rapid progressive motile sperm count and reproduction-related hormone levels [follicle-stimulating hormone, luteinizing hormone, prolactin, testosterone, 17beta-oestradiol and sexual hormone-binding globulin (SHBG)]. Significant correlations were found: (i) weight, waist circumference and hip circumference versus testosterone level, SHBG level, and testosterone/17beta-oestradiol ratio; (ii) hip circumference versus sperm concentration; (iii) waist circumference and hip circumference versus sperm count, total motile sperm cell number and rapid progressive motile sperm count; (iv) weight versus total sperm count and total motile sperm cell number; (v) waist circumference and hip circumference versus prolactin level (positively) and SHBG (negatively); (vi) waist circumference and waist/hip ratio versus semen volume. It can be concluded that the waist/hip ratio is correlated with the reproductive hormone levels. Although both the waist circumference and hip circumference correlated with the semen characteristics, the waist/hip ratio did not.

Is semen quality affected by male body fat distribution

According to many studies, generalised periodontitis can be a risk factor for preterm birth (PB). A case-control study was carried out to examine if early localised periodontitis could be a risk factor for adverse pregnancy outcome. Material and Methods: Postpartum women without any systemic disease were included into the study. Similar numbers of patients belonged to the case (41) and to the control (44) groups. A PB case was defined if a patient had a threatening premature labour during pregnancy, preterm premature rupture of membranes, or spontaneous preterm labour, and/or the weight of the newborn was ≤2499 g. Control women had delivery after the 37th gestational week and the newborn's weight was ≥2500 g. Known risk factors like smoking, alcohol, drug consumption, socio-economic status and the periodontal status were recorded. Results: A significant association was found between PB and early localised periodontitis of the patient with the following criterion having bleeding at ≥50% of the examined sites (6 at each tooth) and having at least at one site ≥4 mm probing depth (p = 0.001). The odds ratio was 5.46 at the 95% confidence interval. The average weight of the newborns in the periodontitis group was less than in the control group, the difference is significant (p = 0.047). Conclusion: The results indicate that early localised periodontitis of the patient during pregnancy can be regarded as an important risk factor for PB.

A possible association between preterm birth and early periodontitis. Pilot study

To evaluate the effect of body mass on the hormonal and semen profiles of subfertile men with oligozoospemia, sperm concentration and reproductive hormone levels were compared in two body mass index (BMI) groups: underweight or normal weight patients (BMI = 25 kg/m2) vs. overweight or obese patients (BMI > 25 kg/m2). The mean BMI was 27 +/- 4.6 kg/m2. The testosterone/estradiol ratio was significantly reduced in the high BMI group as compared to the low BMI group (17 +/- 4 vs. 12 +/- 3; p < 0.05). A similar difference was found in the sperm concentration (11.2 +/- 3.16 x 10(6)/ml vs. 8.1 +/- 2.6 x 10(6)/ml). A nonsignificant difference was found in the LH/FSH ratio (1.41 +/- 0.64 vs. 1.63 +/- 0.72). We concluded that obesity and the consequent estrogen excess decrease the sperm concentration by influencing the hypothalamo-pituitary system.

https://www.tandfonline.com/doi/pdf/10.1080/01485010500315479

Effect of body weight on testosterone/estradiol ratio in oligozoospermic patients

Intra-uterine growth retardation (IUGR) is an abnormality of pregnancy. Neonates with IUGR weigh less than the 10th percentile for gestational age. The objective of the study was to identify the relationship between IUGR and the antioxidant status. Cord blood of 157 neonates with normal weight (control group) and 29 neonates with IUGR were included. The following parameters were determined and compared in the two groups: lipid peroxidation in the plasma, red blood cells and erythrocyte ghosts; protein and DNA damage; antioxidant enzyme activities (superoxide dismutase, catalase, glutathione peroxidase); the level of reduced glutathione; and the ferric reducing ability of the plasma. The level of lipid peroxidation was significantly higher in the IUGR group. The antioxidant enzyme activities and the levels of antioxidants were significantly lower in the IUGR group. Damage of proteins and DNA was slightly, but non-significantly, higher in the IUGR group. Neonates with IUGR seem to have significant deficiencies in antioxidant defence. IUGR is correlated with significant oxidative stress.

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Attila Pál

Papers

Is there a relationship between cell phone use and semen quality

Is semen quality affected by male body fat distribution

A possible association between preterm birth and early periodontitis. Pilot study

Effect of body weight on testosterone/estradiol ratio in oligozoospermic patients

Evaluation of oxidative stress markers in neonates with intra-uterine growth retardation