Linda S. Cook

Standard Quality Assessment Criteria for Evaluating Primary Research Papers from a Variety of Fields

 Does the first sentence contain a clear statement of the purpose of the article (without starting....The purpose of this article is to.....)  Is the test population briefly described?  Does it conclude with a statement of the experiment’s conclusions? STANDARD QUALITY ASSESSMENT CRITERIA FOR EVALUATING PRIMARY RESEARCH PAPERS FROM A VARIETY OF FIELDS Prepared by: Leanne M. Kmet, Robert C. Lee and Linda S. Cook Quantitative Studies Questions 1. Question / objective sufficiently described? 2. Study design evident and appropriate? 3. Method of subject/comparison group selection or source of information/input variables described and appropriate? 4. Subject (and comparison group, if applicable) characteristics sufficiently described? 5. If interventional and random allocation was possible, was it described? 6. If interventional and blinding of investigators was possible, was it reported? 7. If interventional and blinding of subjects was possible, was it reported? 8. Outcome and (if applicable) exposure measure(s) well defined and robust to measurement / misclassification bias? means of assessment reported? 9. Sample size appropriate? 10. Analytic methods described/justified and appropriate? 11. Some estimate of variance is reported for the main results? 12. Controlled for confounding? 13. Results reported in sufficient detail? 14. Conclusions supported by the results? Manual for Quality Scoring of Quantitative Studies Definitions and Instructions for Quality Assessment Scoring How to calculate the summary score: Total sum = (number of “yes” * 2) + (number of “partials” * 1) Total possible sum = 28 – (number of “N/A” * 2) Summary score: total sum / total possible sum 1. Question or objective sufficiently described?  Yes: Is easily identified in the introductory section (or first paragraph of methods section). Specifies (where applicable, depending on study design) all of the following: purpose, subjects/target population, and the specific intervention(s) /association(s)/descriptive parameter(s) under investigation. A study purpose that only becomes apparent after studying other parts of the paper is not considered sufficiently described.  Partial: Vaguely/incompletely reported (e.g. “describe the effect of” or “examine the role of” or “assess opinion on many issues” or “explore the general attitudes”...); or some information has to be gathered from parts of the paper other than the introduction/background/objective section.  No: Question or objective is not reported, or is incomprehensible.  N/A: Should not be checked for this question. 2. Design evident and appropriate to answer study question?  Note: If the study question is not given, infer from the conclusions  Yes: Design is easily identified and is appropriate to address the study question / objective.  Partial: Design and /or study question not clearly identified, but gross inappropriateness is not evident; or design is easily identified but only partially addresses the study question.  No: Design used does not answer study question (e.g., a comparison group is required to answer the study question, but none was used); or design cannot be identified.  N/A: Should not be checked for this question. 3. Method of subject selection (and comparison group selection, if applicable) or source of information/input variables (e.g., for decision analysis) is described and appropriate.  Yes: Described and appropriate. Selection strategy designed (i.e., consider sampling frame and strategy) to obtain an unbiased sample of the relevant target population or the entire target population of interest (e.g., consecutive patients for clinical trials, population-based random sample for case-control studies or surveys). Where applicable, inclusion/exclusion criteria are described and defined (e.g., “cancer” -ICD code or equivalent should be provided). Studies of volunteers: methods and setting of recruitment reported. Surveys: sampling frame/ strategy clearly described and appropriate.  Partial: Selection methods (and inclusion/exclusion criteria, where applicable) are not completely described, but no obvious inappropriateness. Or selection strategy is not ideal (i.e., likely introduced bias) but did not likely seriously distort the results (e.g., telephone survey sampled from listed phone numbers only; hospital based case-control study identified all cases admitted during the study period, but recruited controls admitted during the day/evening only). Any study describing participants only as “volunteers” or “healthy volunteers”. Surveys: target population mentioned but sampling strategy unclear.  No: No information provided. Or obviously inappropriate selection procedures (e.g., inappropriate comparison group if intervention in women is compared to intervention in men). Or presence of selection bias which likely seriously distorted the results (e.g., obvious selection on “exposure” in a case-control study).  N/A: Descriptive case series/reports. 4. Subject (and comparison group, if applicable) characteristics or input variables/information (e.g., for decision analyses) sufficiently described?  Yes: Sufficient relevant baseline/demographic information clearly characterizing the participants is provided (or reference to previously published baseline data is provided). Where applicable, reproducible criteria used to describe/categorize the participants are clearly defined (e.g., ever-smokers, depression scores, systolic blood pressure > 140). If “healthy volunteers” are used, age and sex must be reported (at minimum). Decision analyses: baseline estimates for input variables are clearly specified.  Partial: Poorly defined criteria (e.g. “hypertension”, “healthy volunteers”, “smoking”). Or incomplete relevant baseline / demographic information (e.g., information on likely confounders not reported). Decision analyses: incomplete reporting of baseline estimates for input variables.  No: No baseline / demographic information provided. Decision analyses: baseline estimates of input variables not given.  N/A: Should not be checked for this question. 5. If random allocation to treatment group was possible, is it described?  Yes: True randomization done requires a description of the method used (e.g., use of random numbers).  Partial: Randomization mentioned, but method is not (i.e. it may have been possible that randomization was not true).  No: Random allocation not mentioned although it would have been feasible and appropriate (and was possibly done).  N/A: Observational analytic studies, uncontrolled experimental studies, surveys, descriptive case series / reports, decision analyses 6. If interventional and blinding of investigators to intervention was possible, is it reported?  Yes: Blinding reported.  Partial: Blinding reported, but it is not clear who was blinded.  No: Blinding would have been possible (and was possibly done) but is not reported.  N/A: Observational analytic studies, uncontrolled experimental studies, surveys, descriptive case series and reports, decision analyses. 7. If interventional and blinding of subjects to intervention was possible, is it reported?  Yes: Blinding reported.  Partial: Blinding reported but it is not clear who was blinded.  No: Blinding would have been possible (and was possibly done) but is not reported.  N/A: Observational studies, uncontrolled experimental studies, surveys, descriptive case series / reports. 8. Outcome and (if applicable) exposure measure(s) well defined and robust to measurement / misclassification bias? Means of assessment reported?  Yes: Defined (or reference to complete definitions is provided) and measured according to reproducible, “objective” criteria (e.g., death, test completion – yes/no, clinical scores). Little or minimal potential for measurement / misclassification errors. Surveys: clear description (or reference to clear description) of questionnaire/interview content and response options. Decision analyses: sources of uncertainty are defined for all input variables.  Partial: Definition of measures leaves room for subjectivity, or not sure (i.e., not reported in detail, but probably acceptable). Or precise definition(s) are missing, but no evidence or problems in the paper that would lead one to assume major problems. Or instrument/mode of assessment(s) not reported. Or misclassification errors may have occurred, but they did not likely seriously distort the results (e.g., slight difficulty with recall of long-ago events; exposure is measured only at baseline in a long cohort study). Surveys: description of questionnaire/interview content incomplete; response options unclear. Decision analyses: sources of uncertainty are defined only for some input variables.  No: Measures not defined, or are inconsistent throughout the paper. Or measures employ only ill-defined, subjective assessments, e.g. “anxiety” or “pain.” Or obvious misclassification errors /measurement bias likely seriously distorted the results (e.g., a prospective cohort relies on selfreported outcomes among the “unexposed” but requires clinical assessment of the “exposed”). Surveys:  No description of questionnaire/interview content or response options. Decision analyses: sources of uncertainty are not defined for input variables.  N/A: Descriptive case series / reports. 9. Sample size appropriate?  Yes: Seems reasonable with respect to the outcome under study and the study design. When statistically significant results are achieved for major outcomes, appropriate sample size can usually be assumed, unless large standard errors (SE > 1⁄2 effect size) and/or problems with multiple testing are evident. Decision analyses: size of modeled cohort / number of iterations specified and justified.  Partial: Insufficient data to assess sample size (e.g., sample seems “small” and there is no mention of power/sample size/effect size of interest and/or variance estimates aren’t provided). Or some statistically significant re

Type I and II Endometrial Cancers: Have They Different Risk Factors?

PURPOSE Endometrial cancers have long been divided into estrogen-dependent type I and the less common clinically aggressive estrogen-independent type II. Little is known about risk factors for type II tumors because most studies lack sufficient cases to study these much less common tumors separately. We examined whether so-called classical endometrial cancer risk factors also influence the risk of type II tumors. PATIENTS AND METHODS Individual-level data from 10 cohort and 14 case-control studies from the Epidemiology of Endometrial Cancer Consortium were pooled. A total of 14,069 endometrial cancer cases and 35,312 controls were included. We classified endometrioid (n = 7,246), adenocarcinoma not otherwise specified (n = 4,830), and adenocarcinoma with squamous differentiation (n = 777) as type I tumors and serous (n = 508) and mixed cell (n = 346) as type II tumors. RESULTS Parity, oral contraceptive use, cigarette smoking, age at menarche, and diabetes were associated with type I and type II tumors to similar extents. Body mass index, however, had a greater effect on type I tumors than on type II tumors: odds ratio (OR) per 2 kg/m(2) increase was 1.20 (95% CI, 1.19 to 1.21) for type I and 1.12 (95% CI, 1.09 to 1.14) for type II tumors (P heterogeneity < .0001). Risk factor patterns for high-grade endometrioid tumors and type II tumors were similar. CONCLUSION The results of this pooled analysis suggest that the two endometrial cancer types share many common etiologic factors. The etiology of type II tumors may, therefore, not be completely estrogen independent, as previously believed.

Paternal age is positively linked to telomere length of children

Telomere length is linked to age‐associated diseases, with shorter telomeres in blood associated with an increased probability of mortality from infection or heart disease. Little is known about how human telomere length is regulated despite convincing data from twins that telomere length is largely heritable, uniform in various tissues during development until birth and variable between individuals. As sperm cells show increasing telomere length with age, we investigated whether age of fathers at conception correlated with telomere length of their offspring. Telomere length in blood from 125 random subjects was shown to be positively associated with paternal age (+22 bp yr−1, 95% confidence interval 5.2–38.3, P = 0.010), and paternal age was calculated to affect telomere length by up to 20% of average telomere length per generation. Males lose telomeric sequence faster than females (31 bp yr−1, 17.6–43.8, P < 0.0001 vs. 14 bp yr−1, 3.5–24.8, P < 0.01) and the rate of telomere loss slows throughout the human lifespan. These data indicate that paternal age plays a role in the vertical transmission of telomere length and may contribute significantly to the variability of telomere length seen in the human population, particularly if effects are cumulative through generations.

Colorectal cancer incidence in Asian migrants to the United States and their descendants.

AbstractObjectives: To examine the incidence of colorectal cancer among Asian residents of the United States according to country of birth. Methods: We determined the incidence of colorectal cancer during 1973–1986 among Asian residents in three areas of the western United States (Hawaii, San Francisco/Oakland SMSA, and western Washington state) in relation to country of birth. Numerators for the rates were obtained from the Surveillance, Epidemiology and End Results (SEER) program; a special tabulation of the 1980 US Census was used to estimate the size and composition of the population at risk. Results: US-born Japanese men experienced incidence rates of colorectal cancer twice as high as foreign-born Japanese men and about 60% higher than those of US-born white men. Incidence among US-born Japanese women was about 40% higher than that among Japanese women born in Japan or US-born white women. Foreign-born Chinese men had about the same incidence of colorectal cancer as US-born white men, while US-born Chinese men experienced slightly reduced rates. Chinese women had rates that were generally 30–40% lower than that of US-born white women, regardless of place of birth. Incidence rates for both US-born and foreign-born Filipinos were 20–50% those of US-born whites. Conclusions: These findings suggest that one or more exposures or characteristics that differ between Japanese migrants and their descendants affect the development of colorectal cancer.

Circumcision and sexually transmitted diseases

OBJECTIVES New evidence linking lack of circumcision with sexually transmitted human immunodeficiency virus revives concerns about circumcision and other sexually transmitted diseases. This study was undertaken to assess the relationship between circumcision and syphilis, gonorrhea, chlamydial infection, genital herpes, nongonococcal urethritis, and exophytic genital warts. METHODS A cross-sectional study of 2776 heterosexual men attending a sexually transmitted disease clinic in 1988 was used to investigate the relationship between circumcision and sexually transmitted diseases. Subjects with specific sexually transmitted diseases and those without such diseases were compared after adjustment for age, race, zip code of residence, other sexually transmitted diseases, and number of sexual partners. RESULTS A positive relationship was observed between uncircumcised status and both syphilis and gonorrhea. A negative relationship was found between warts and lack of circumcision. No apparent relationship was noted between uncircumcised status and genital herpes, chlamydial infection, or nongonococcal urethritis. CONCLUSIONS Uncircumcised men were more likely than circumcised men to have syphilis and gonorrhea and were less likely to have visible warts.

Biofilm Formation by Group A Streptococci: Is There a Relationship with Treatment Failure?

ABSTRACT Group A streptococcus (GAS) is the primary cause of bacterial pharyngitis in children and adults. Up to one-third of patients treated for GAS pharyngitis fail to respond to antibiotic therapy. The objective of this cohort study was to evaluate GAS biofilm formation as a mechanism for antibiotic treatment failure using previously collected GAS isolates and penicillin treatment outcome data. The minimum biofilm eradication concentration (MBEC) assay device was used to determine the biofilm-forming capabilities, efficiencies, and antibiotic susceptibilities of GAS isolates. The MBECs and MICs of several antibiotics for GAS were determined. All 99 GAS isolates available for this study formed biofilms, with various efficiencies. Antibiotic MBECs were consistently higher than MICs for all of the GAS isolates. MBECs indicated penicillin insensitivity in 60% of GAS isolates, producing the first report of in vitro GAS insensitivity to penicillin. Using MBECs to predict penicillin treatment failure had better sensitivity (56%) but lower specificity (36%) than the sensitivity (0%) and specificity (100%) when MICs were used. However, the positive predictive value of the MBEC was superior to that of the MIC (56 versus 0%), while the negative predictive values (42 and 47%) were similar. More studies are needed to understand the roles of biofilms and the MBEC assay in predicting GAS treatment failure. In addition, further investigations are necessary to determine if non-biofilm-forming strains of GAS exist and the roles of in vivo monospecies and multispecies biofilms in streptococcal pharyngitis treatment failure.

Reproductive risk factors for mucinous and non-mucinous epithelial ovarian cancer.

We evaluated reproductive risk factors for mucinous and non-mucinous tumors in a population-based case-control study of epithelial ovarian cancer among women ages 20-79 years. We observed a reduction in risk of tumors of both types in association with one or more full-term pregnancies and with use of oral contraceptives for 5 or more years. While findings of some previous studies support the hypothesis that certain aspects of a womans reproductive life have a different impact on the risk of these subtypes of ovarian epithelial cancer, our data suggest that this issue is not yet resolved.

Dietary intake and risk of postmenopausal breast cancer (United States)

Objectives: While there is good evidence from cell-culture and animal studies to indicate that dietary intake impacts breast cancer risk, results of epidemiologic studies have been inconsistent. Additionally, while the etiology of breast cancer in premenopausal versus postmenopausal women may be quite different, most studies have not chosen to focus solely on one group or the other. In this case–control study, we evaluate the associations between red meat, fish, dairy products, and fruits and vegetables, and risk of breast cancer in postmenopausal women. Methods: A food-frequency questionnaire was completed by 441 women with in-situ or invasive breast cancer and 370 population controls. Cases were identified from the population-based Cancer Surveillance System (CSS) of western Washington and frequency age-matched controls identified by random-digit dialing (RDD). Unconditional logistic regression was used to model the association between each food grouping and breast cancer risk adjusting for age, number of pregnancies, and education. Results: Red meat intake was significantly associated with an increased breast cancer risk (p for trend = 0.002) and fish (including fried fish) and dairy product intake was inversely associated with breast cancer risk (p for trend = 0.04 and 0.05, respectively). No significant associations were noted between fruit or vegetable intake and breast cancer risk. Conclusions: The findings from this study support the results of several larger cohort studies and contribute to the evidence for the development of dietary recommendations for breast cancer risk reduction specific to postmenopausal women.

A Review of Cancer in U.S. Hispanic Populations

There are compelling reasons to conduct studies of cancer in Hispanics, the fastest growing major demographic group in the United States (from 15% to 30% of the U.S. population by 2050). The genetically admixed Hispanic population coupled with secular trends in environmental exposures and lifestyle/behavioral practices that are associated with immigration and acculturation offer opportunities for elucidating the effects of genetics, environment, and lifestyle on cancer risk and identifying novel risk factors. For example, traditional breast cancer risk factors explain less of the breast cancer risk in Hispanics than in non-Hispanic whites (NHW), and there is a substantially greater proportion of never-smokers with lung cancer in Hispanics than in NHW. Hispanics have higher incidence rates for cancers of the cervix, stomach, liver, and gall bladder than NHW. With respect to these cancers, there are intriguing patterns that warrant study (e.g., depending on country of origin, the five-fold difference in gastric cancer rates for Hispanic men but not Hispanic women). Also, despite a substantially higher incidence rate and increasing secular trend for liver cancer in Hispanics, there have been no studies of Hispanics reported to date. We review the literature and discuss study design options and features that should be considered in future studies. Cancer Prev Res; 5(2); 150–63. ©2012 AACR.

Case–Control Study of the Metabolic Syndrome and Metabolic Risk Factors for Endometrial Cancer

Background: Metabolic syndrome may predict endometrial cancer risk better than diabetes, hypertension, dyslipidemia, dysglycemia, or weight alone, but few studies have examined this issue. Methods: We conducted a population-based case–control study in Alberta, Canada (2002–2006) that included 515 incident endometrial cancer cases and 962 frequency age-matched controls. Data were collected through in-person interviews, anthropometric measurements, and 8-hour fasting bloods drawn either pre- or postsurgery. Bloods were analyzed using quantitative colorimetric or absorbance-based assays (ELISA), specific to metabolic syndrome markers. Metabolic syndrome was defined using harmonized guidelines requiring presence of ≥3 of the following risk factors: waist circumference ≥88 cm, triglycerides ≥150 mg/dL, high-density lipoprotein cholesterol <50 mg/dL, treatment of previously diagnosed hypertension, and fasting blood glucose ≥100 mg/dL. OR and 95% CIs for endometrial cancer risk with presence of metabolic syndrome and individual metabolic syndrome components were estimated using logistic regression analysis. Results: Metabolic syndrome was significantly more prevalent among cases (62%) than controls (38%). A statistically significant increased risk for endometrial cancer was observed for metabolic syndrome (OR = 1.53; 95% CI: 1.17–2.00), as well as for some of the individual components of metabolic syndrome including waist circumference ≥88 cm (OR = 1.57; 95% CI: 1.18–2.08), hypertension (OR = 1.57; 95% CI: 1.18–2.09), and fasting blood glucose ≥100 mg/dL (OR = 1.31; 95% CI: 1.03–1.67). Some evidence for effect modification by menopausal status and body mass index was also found. Conclusion: Metabolic syndrome is clearly associated with increased endometrial cancer risk. Impact: Targeting the entire metabolic syndrome may optimize endometrial cancer risk reduction. Cancer Epidemiol Biomarkers Prev; 20(11); 2384–95. ©2011 AACR.