Characteristics of respondents and non-respondents to a mailed questionnaire

Through the Eyes of Patients: Understanding Treatment Burden of Intravitreal Anti-VEGF Injections for nAMD Patients in Norway

Purpose

Patients with neovascular age-related macular degeneration (nAMD) are treated with frequent intravitreal injections to maintain vision. The treatment frequency impacts the life of patients and caregivers and poses a major capacity challenge for Norwegian ophthalmic clinics. The purpose of this survey was to document patient-reported outcomes on how the disease and the treatment impact nAMD patients in Norway.

Methods

Norwegian nAMD patients voluntarily completed the survey. The patients reported the time spent on each treatment appointment, the need for caregiver support, treatment intervals, and the emotional impact of the treatment. There was no active selection of patients to the survey. Respondents had to confirm the nAMD diagnosis prior to submitting the response. All data was included in the analysis as submitted by the respondents. This survey was market research involving anonymous patient data, and no participants were identifiable.

Results

In total, 130 patients responded to the survey. The majority of patients reported to receive nine or more injections per year (48.8%), and many patients needed caregiver support for every treatment appointment (37.7%). Patients reported to be anxious one day (25.4%), two days (8.5%), one week (10.8%) or more than one week (3.1%) prior to treatment. The week before the treatment, 33.1% of patients reported to be stressed and 15.4% struggled to sleep. The majority of patients reported the treatment as uncomfortable (54.6%) or as somewhat painful (26.2%). The results on yearly number of injections, time used each treatment day and need for caregiver support suggested a variation between Norwegian hospital regions.

Conclusions

This survey uncovers how treatment with intravitreal injections represents a substantial burden for Norwegian patients with nAMD. Future research on how the treatment burden impacts nAMD patients may lead to more patient-centered care and help guide treatment decisions. New treatments with longer intervals between injections are likely to both reduce the treatment burden and improve capacity in ophthalmology clinics.

Cohort Study of Nonmelanoma Skin Cancer and the Risk of Exfoliation Glaucoma

PRECIS

In a cohort study of 120,307 participants with 25+ years of follow-up, a history of nonmelanoma skin cancer (NMSC) was associated with a 40% higher exfoliation glaucoma (XFG) risk.

PURPOSE

The purpose of this study was to evaluate the relationship between NMSC (a marker of ultraviolet radiation exposure) and XFG.

METHODS

We performed a cohort study of US women (n=79,102; 1980-2014) and men (n=41,205; 1986-2014), aged 40+ years and at risk for glaucoma who reported eye examinations. From 1984 (women)/1988 (men), we asked about basal cell carcinoma or squamous cell carcinoma history separately; in prior years, we asked about any NMSC history in a single question. Squamous cell carcinoma was confirmed with histopathology reports while basal cell carcinoma and any early (<1984/<1988) NMSC history was self-reported. Incident XFG cases (362 women and 83 men) were confirmed with medical records. Using pooled data, we estimated multivariable-adjusted relative risks [MVRRs; 95% confidence intervals (CIs)] with Cox proportional hazards models that were stratified by age (in mo), 2-year time period at risk and average lifetime residential latitude.

RESULTS

In multivariable-adjusted analyses, we observed a 40% higher XFG risk with any NMSC history (MVRR=1.40; 95% CI=1.08-1.82); the association was observed even with 4 and 8-year lags in NMSC history. Also, the NMSC association was stronger in younger (below 65 y; MVRR=2.56; 95% CI=1.62-4.05) versus older participants (65 y and above; MVRR=1.25; 95% CI=0.94-1.66; P for interaction=0.01) and those living in the northern latitudes (≥42°N; MVRR=1.92; 95% CI=1.28-2.88) versus more southern latitudes (<42°N; MVRR=1.19; 95% CI=0.86-1.66; P for interaction=0.04).

CONCLUSION

NMSC was associated with higher XFG risk, particularly among younger participants and those living in the Northern US.

The predictors of Enhanced Recovery After Surgery utilization and practice variations in elective colorectal surgery: a provincial survey

BACKGROUND

Enhanced Recovery After Surgery (ERAS) protocols use evidence-based perioperative practices that reduce morbidity and length of stay and improve patient satisfaction. ERAS is considered standard of care; however, utilization remains low and substantial practice variation exists. The aim of this study was to pragmatically characterize variation in colorectal surgery practice and identify predictors of ERAS utilization.

METHODS

A survey of general surgeons identified using the Ontario College of Physicians and Surgeons database was conducted. Information on basic demographic characteristics, utilization of ERAS and predictors of ERAS implementation was collected. Nine ERAS behaviours were analyzed. Multivariable analysis was used to determine effects of demographic, hospital and surgeon covariates on ERAS utilization.

RESULTS

Seven hundred and ninety-seven general surgeons were invited to participate in the survey, and 235 general surgeons representing 84 Ontario hospitals responded (30% response rate). Surgeons practising in academic settings and in large community hospitals represented 30% and 47% of the respondents, respectively. A total of 20% of the respondents used all 9 ERAS behaviours consistently. Rates of diet advancement on postoperative day 0, intravenous fluid restriction and having catheter and line procedures were significantly higher among respondents who adhered to ERAS protocols than among those who did not (74% v. 54%, p = 0.004; 92% v. 80%, p = 0.01; and 91% v. 41%, p < 0.001, respectively). Respondents from academic settings reported practising nearly 1 more ERAS behaviour than those from small community hospitals (odds ratio [OR] 0.86, 95% confidence interval [CI] 0.42 to 1.31, p < 0.001). Multivariable analysis demonstrated that colorectal fellowship training or exposure to ERAS during training did not significantly affect ERAS behaviour utilization (OR 0.32, 95% CI -0.31 to 0.94, p = 0.16; OR 0.28, 95% CI -0.26 to 0.82, p = 0.16, respectively).

CONCLUSION

Substantial practice variation in colorectal surgery still exists. Individual ERAS principles are commonly followed; however, ERAS behaviours are not widely formalized into hospital protocols.

Practice of reporting social characteristics when describing representativeness of epidemiological cohort studies - A rationale for an intersectional perspective

Representativeness has been defined as the degree of similarity of a study population compared to an external population. To characterize a study population, both health-related and social or demographic features should be considered according to current guidelines. However, little guidance is given on how to describe social complexity of study populations when aiming to conclude on representativeness. We argue that sociological concepts should inform characterizations of study populations in order to increase credibility of conclusions on representativeness. The concept of intersectionality suggests to conceptualize social location as a combination of characteristics such as sex/gender and ethnicity instead of focusing on each feature independently. To contextualize advantages of integrating the concept of intersectionality when investigating representativeness, we reviewed publications that described the baseline population of selected epidemiological cohort studies. Information on the applied methods to characterize the study population was extracted, as well as reported social characteristics. Nearly all reviewed studies reported descriptive statistics of the baseline population and response proportions. In most publications, study populations were characterized according to place of residence, age and sex/gender while other social characteristics were reported irregularly. Differential patterns of representativeness were revealed in analyses that stratified social characteristics by sex/gender or age. Furthermore, the included studies did not explicitly state the theoretical approach that underlay their description of the study population. Intersectionality might be particularly fruitful when applied to descriptions of representativeness, because this concept provides an understanding of social location that has been developed based on situated experiences of people at the intersection of multiple axes of social power relations. An intersectional perspective, hence, contributes to approximate social complexity of study populations and might contribute to increase validity of conclusions on representativeness of population-based studies.

Association of Statin Use and High Serum Cholesterol Levels With Risk of Primary Open-Angle Glaucoma

Importance

The use of statins (hydroxymethylglutaryl coenzyme A inhibitors) has been associated with a lower risk of primary open-angle glaucoma (POAG); however, results have been conflicting, and little is known about the association between high cholesterol levels and POAG.

Objective

To assess the association of elevated cholesterol levels and statin use with incident POAG.

Design, Setting, and Participants

This study used data collected biennially from participants aged 40 years or older who were free of glaucoma and reported eye examinations, within 3 population-based cohorts: the Nurses' Health Study (N = 50 710; followed up from 2000 to 2014), the Nurses' Health Study 2 (N = 62 992; 1999-2015), and the Health Professionals Follow-up Study (N = 23 080; 2000-2014). Incident cases of POAG were confirmed by medical record review. The analyses were performed in January 2019.

Exposures

Biennially updated self-reported information on elevated cholesterol level status, serum cholesterol levels, and duration of statin use.

Main Outcomes and Measures

Multivariable-adjusted relative risks (RRs) and 95% CIs were estimated using Cox proportional hazards regression models on pooled data, with stratification by cohort.

Results

Among the 136 782 participants in the 3 cohorts (113 702 women and 23 080 men), 886 incident cases of POAG were identified. Every 20-mg/dL increase in total serum cholesterol was associated with a 7% increase in risk of POAG (RR, 1.07 [95% CI, 1.02-1.11]; P = .004). Any self-reported history of elevated cholesterol was also associated with a higher risk of POAG (RR, 1.17 [95% CI, 1.00-1.37]). A history of any statin use was associated with a 15% lower risk of POAG (RR, 0.85 [95% CI, 0.73-0.99]). Use of statins for 5 or more years vs never use of statins was associated with a 21% lower risk of POAG (RR, 0.79 [95% CI, 0.65-0.97]; P = .02 for linear trend). The association between use of statins for 5 or more years vs never use of statins and risk of POAG was more inverse in those who were older (≥65 years: RR, 0.70 [95% CI, 0.56-0.87] vs <65 years: RR, 1.05 [95% CI, 0.68-1.63]; P = .01 for interaction).

Conclusions and Relevance

Among adults aged 40 years or older, higher serum cholesterol levels were associated with higher risk of POAG, while 5 or more years of statin use compared with never use of statins was associated with a lower risk of POAG.

Sex hormone levels and risk of primary open-angle glaucoma in postmenopausal women

OBJECTIVE

We evaluated the relation of prediagnostic sex hormone levels in postmenopausal women with primary open-angle glaucoma (POAG) and intraocular pressure (IOP).

METHODS

Among postmenopausal participants of the Nurses' Health Study, POAG cases (n = 189; diagnosed 1990-2008) and controls (n = 189) were matched on age, fasting status, and postmenopausal hormone use at blood draw (1989-1990). Plasma concentrations of estrone sulfate, estradiol, testosterone, sex hormone binding globulin, and dehydroepiandrosterone sulfate were assessed. The primary outcome was POAG; in secondary analyses, among cases only, we evaluated maximum untreated IOP at diagnosis. Multivariable-adjusted logistic/multiple linear regression models were used to evaluate tertiles (Ts) of biomarker levels and the two outcomes, adjusting for various potential confounders.

RESULTS

We observed no significant associations of estrone, estradiol, sex hormone binding globulin, or dehydroepiandrosterone sulfate with POAG risk or with maximum IOP at glaucoma diagnosis among cases. Suggestive significant associations were observed with highest testosterone and POAG risk (T3 vs T1 multivariable-adjusted odds ratio 1.84; 95% confidence interval 1.02, 3.33; P trend 0.10). Similarly, for maximum IOP at diagnosis among cases only (mean 8 years after blood draw), higher testosterone was significantly associated with higher IOP (multivariable-adjusted difference in IOP T3 vs T1 2.17 mm Hg; 95% confidence interval 0.34, 3.99; P trend 0.02).

CONCLUSIONS

Overall, plasma sex hormone levels in postmenopausal women were not associated with POAG risk; however, a trend of higher testosterone levels being associated with higher POAG risk and higher IOP at diagnosis was observed and needs confirmation.

Model based estimation of population total in presence of non-ignorable non-response

The problem of handling non-ignorable non-response has been typically addressed under the design-based approach using the well-known sub-sampling technique introduced by Hansen and Hurwitz [1946, Journal of the American Statistical Association, Vol 41(236), Page 517- 529]. Alternatively, the model-based paradigm emphasizes on utilizing the underlying model relationship between the outcome variable and one or more covariate(s) whose population values are known prior to the survey. This article utilizes the model relationship between the study variable and covariate(s) for handling non-ignorable non-response and obtaining an unbiased estimator for the population total under the sub-sampling technique. The main idea is to combine the estimates obtained from the sample on first call and the sub-sample from second call using separate model relationships. The contribution of this paper helps us in providing unbiased estimates with an improved efficiency under model-based paradigm in presence of non-ignorable non-response. The provided method is more economical than the available estimators under callback methods as we are working sub-sampling and also increase response rate as a stronger mode of interview is employed for data collection. A numerical study using Monte Carlo is presented to illustrate the behavior of the proposed and the efficiency comparison.

A Provincial Assessment of the Barriers and Utilization of Enhanced Recovery After Colorectal Surgery

BACKGROUND

Enhanced recovery after surgery (ERAS) protocols after colorectal surgery use several perioperative, intraoperative and postoperative interventions that decrease morbidity, length of stay, and improve patient satisfaction. ERAS is increasingly being considered standard of care; however, uptake of formalized protocols remains low. The objective is to characterize the provincial rates of ERAS utilization after colorectal surgery and identify barriers and limitations to ERAS implementation.

METHODS

A total of 797 general surgeons were identified through the College of Physicians and Surgeons of Ontario. A survey identifying demographics, rates of ERAS utilization, and barriers to implementation was distributed. Logistic regression determined the effects of demographic and hospital covariates on ERAS utilization.

RESULTS

A total of 235 general surgeons representing 84 Ontario hospitals participated (response rate 29.5%). Surgeons working in academic or large community hospitals represented the majority of the cohort (30.5% and 47.2%, respectively). Multivariable analysis showed no significant effect of surgeon demographics, years in practice, or training details on ERAS protocol utilization; however, practicing in small community hospitals (compared with large and academic hospitals) was significantly associated with not using ERAS protocols (odds ratio, 0.02; 95% confidence interval, 0-0.3; P = 0.005). Over 50% of respondents used ERAS principles but did not have a formal protocol. Barriers to implementing ERAS protocols included patient variability, lack of institutional and nursing support, and poor communication with the care team.

CONCLUSIONS

Small community hospitals are less likely to use formal ERAS protocols; however, most Ontario surgeons are using ERAS principles after colorectal surgery. Barriers to ERAS implementation are broad and the present study has provided a pragmatic solution to change.

Prospective study of flavonoid intake and risk of primary open-angle glaucoma

PURPOSE

To evaluate the association between flavonoid intake and incident primary open-angle glaucoma (POAG).

METHODS

We followed 65 516 women from the Nurses' Health Study (from 1984) and 42 156 men from the Health Professionals Follow-up Study (from 1986) biennially to 2012, who were 40+ years old, free of POAG, and reported eye examinations. Dietary flavonoid intake was assessed with validated repeated semi-quantitative food frequency questionnaires. Incident POAG cases (n = 1575) were confirmed with medical record review. Cohort-specific multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CIs) were calculated and meta-analysed.

RESULTS

Total flavonoid intake was not associated with risk of POAG development [RR for highest (Q5: median ~645 mg/day) versus lowest quintile (Q1: ~130 mg/day) = 0.91 (95% CI = 0.77, 1.08); p for trend (p-trend) = 0.19]; the flavonoid subclasses of flavones, flavanones, polymeric flavanols or anthocyanidins were also not associated (Q5 versus Q1 comparison p-values ≥0.05 and p-trend ≥0.09). Higher intakes of flavonols and monomeric flavanols were nominally associated with lower POAG risk, based on the Q5 versus Q1 comparisons or p-trends. The Q5 versus Q1 comparison RRs were: for flavonols, 0.82 (95% CI = 0.69, 0.97; p-trend = 0.05; ~28 versus ~8 mg/day), and for monomeric flavanols, 0.86 (95% CI = 0.72, 1.02; p-trend=0.04; ~110 versus 10 mg/day). The food/beverage that contributed most to both the variation of flavonols and monomeric flavanols was tea; consuming ~2 cups/day was associated with 18% lower POAG risk (RR=0.82; 95% CI = 0.68, 0.99; p-trend = 0.02).

CONCLUSION

Total flavonoid intake was not associated with POAG risk. Greater intakes of flavonols and monomeric flavanols and of tea showed suggestive modest associations with lower risk; these results need confirmation.

Web-Based Recruitment and Survey Methodology to Maximize Response Rates from Followers of Popular Diets: the Adhering to Dietary Approaches for Personal Taste (ADAPT) Feasibility Survey

BACKGROUND

Although there is interest in popular diets such as vegan and vegetarian, Paleo, and other "whole food" diets, existing cohort studies lack data for these subgroups. The use of electronic data capture and Web-based surveys in nutrition research may be valuable for future studies by allowing targeting of specific dietary subgroups.

OBJECTIVE

The aim was to perform a Feasibility Survey (FS) to assess the practicality of Web-based research methods to gather data and to maximize response rates among followers of popular diets.

METHODS

The FS was an open, voluntary, 15-min survey conducted over 8 wk in the summer of 2015. Recruitment targeted self-identified followers of popular diets from a convenience sample, offering no incentives, via social media and e-newsletters shared by recruitment partners. Feasibility was assessed by number of responses, survey completion rate, distribution of diets, geographic location, and willingness to participate in future research.

RESULTS

A total of 14,003 surveys were initiated; 13,787 individuals consented, and 9726 completed the survey (71% of consented). The numbers of unique visitors to the questionnaire site, view rate, and participation rate were not captured. Among respondents with complete demographic data, 83% were female and 93% were white. Diet designations were collapsed into the following groups: whole-food, plant-based (25%); vegan and raw vegan (19%); Paleo (14%); try to eat healthy (11%); vegetarian and pescatarian (9%); whole food (8%); Weston A Price (5%); and low-carbohydrate (low-carb) (4%). Forced-response, multiple-choice questions produced the highest response rates (0-2% selected "prefer not to answer"). The percentage who were willing to complete future online questionnaires was 86%, diet recall was 93%, and food diary was 75%; the percentages willing to provide a finger-stick blood sample, venipuncture blood sample, urine sample, and stool sample were 60%, 44%, 58%, and 42%, respectively.

CONCLUSIONS

This survey suggests that recruiting followers of popular diets is feasible with the use of Web-based methods. The unbalanced sample with respect to sex and race/ethnicity could be corrected with specific recruitment strategies using targeted online marketing techniques.

Determinants of Physicians’ Preferences for Alternative Treatments in Women with Early Breast Cancer

To learn about factors, that influence a physician's decision making, a mail survey was conducted asking physicians about their preferences for radical mastectomy vs. local excision plus irradiation, and for adjuvant chemotherapy vs. no adjuvant treatment for two hypothetical women with operable, clinical stage I breast cancer - one 35 years old and the other 60 years old. Two hundred and sixty-one physicians from varied specialties in Connecticut and Massachusetts returned the questionnaire. Approximately half of the respondents would accept either mastectomy or limited surgery plus radiation therapy for either patient. Adjuvant chemotherapy was recommended by 97% of respondents for the younger patient and by 66% for the older patient. Several factors appeared to be related to therapeutic preferences. An individual physician's attitude towards patient involvement in decision making was the most important predictor of surgical preference for both the patients, whereas the role of specialty (i.e., surgeons vs. other providers) was more important for the surgical management of the older patient. For the decision involving adjuvant chemotherapy, specialty, hospital size, and presence of radiotherapy equipment on site were important predictors. Factors other than survival (such as disease-free interval and cosmetic results) were viewed as important standards of effectiveness by some physicians.

Food and beverage consumption and food addiction among women in the Nurses' Health Studies

BACKGROUND AND AIMS

Previous studies have not addressed a fundamental component of a food addiction disorder: the compulsive relationship between eating and potentially positively reinforcing foods. We aimed to evaluate the association between food consumption and food addiction.

METHODS

We conducted cross-sectional analyses merging data from the Nurses' Health Study (n = 58,625) and Nurses' Health Study II (n = 65,063), two prospective cohort studies of female nurses in the United States. Diet was assessed in 2006-2007 using a food frequency questionnaire, and food addiction was assessed in 2008-2009 using the Modified Yale Food Addiction Scale.

RESULTS

The prevalence of food addiction was 5.4%. The odds of food addiction were strongest among nurses consuming 5+ servings/week (compared with <1 serving/month) of hamburgers (multivariable odds ratio (MVOR) 4.08; 95% CI, 2.66-6.25), French fries (MVOR, 2.37; 95% CI, 1.59-3.51) and pizza (MVOR, 2.49; 95% CI, 1.67-3.69). Consumption of red/processed meat, low/no fat snacks/desserts, and low calorie beverages was positively associated with food addiction, while consumption of refined grains, sugar-sweetened beverages and fruits, vegetables, and legumes was inversely associated with food addiction.

CONCLUSIONS

This epidemiologic study was the largest to examine food consumption and food addiction. Food addiction was positively associated with consumption of many hypothesized positively reinforcing foods that include a combination of carbohydrates and fats such as snacks, "fast foods," and candy bars. However, it was inversely or not associated with certain sweet foods, refined grains, and sugar-sweetened beverages, which is consistent with literature suggesting that carbohydrates (without other ingredients) are less associated with food addiction. Longitudinal analyses will help untangle the temporal order between food consumption and food addiction, as some relationships in our analyses were difficult to interpret due to the cross-sectional design.

Evaluation of Selection Bias in an Internet-based Study of Pregnancy Planners

Selection bias is a potential concern in all epidemiologic studies, but it is usually difficult to assess. Recently, concerns have been raised that internet-based prospective cohort studies may be particularly prone to selection bias. Although use of the internet is efficient and facilitates recruitment of subjects that are otherwise difficult to enroll, any compromise in internal validity would be of great concern. Few studies have evaluated selection bias in internet-based prospective cohort studies. Using data from the Danish Medical Birth Registry from 2008 to 2012, we compared six well-known perinatal associations (e.g., smoking and birth weight) in an internet-based preconception cohort (Snart Gravid n = 4,801) with the total population of singleton live births in the registry (n = 239,791). We used log-binomial models to estimate risk ratios (RRs) and 95% confidence intervals (CIs) for each association. We found that most results in both populations were very similar. For example, maternal obesity was associated with an increased risk of delivering a macrosomic infant in Snart Gravid (RR = 1.5; 95% CI: 1.2, 1.7) and the total population (RR = 1.5; 95% CI: 1.45, 1.53), and maternal smoking of >10 cigarettes per day was associated with a higher risk of low birth weight (RR = 2.7; 95% CI: 1.2, 5.9 vs. RR = 2.9; 95% CI: 2.6, 3.1) in Snart Gravid and the total population, respectively. We cannot be certain that our results would apply to other associations or different populations. Nevertheless, our results suggest that recruitment of reproductive aged women via the internet may be no more prone to selection bias than traditional methods of recruitment.

Association of Dietary Nitrate Intake With Primary Open-Angle Glaucoma: A Prospective Analysis From the Nurses' Health Study and Health Professionals Follow-up Study

IMPORTANCE

Nitric oxide signaling alterations in outflow facility and retinal blood flow autoregulation are implicated in primary open-angle glaucoma (POAG). Nitric oxide donation has emerged as a POAG therapeutic target. An exogenous source of nitric oxide is dietary nitrates.

OBJECTIVE

To evaluate the association between dietary nitrate intake, derived mainly from green leafy vegetables, and POAG.

DESIGN, SETTING, AND PARTICIPANTS

We followed up participants biennially in the prospective cohorts of the Nurses' Health Study (63 893 women; 1984-2012) and the Health Professionals Follow-up Study (41 094 men; 1986-2012) at each 2-year risk period. Eligible participants were 40 years or older, were free of POAG, and reported eye examinations.

EXPOSURES

The primary exposure was dietary nitrate intake. Information on diet and potential confounders was updated with validated questionnaires.

MAIN OUTCOMES AND MEASURES

The main outcome was the incidence of POAG and POAG subtypes; 1483 cases were confirmed with medical records and classified into subtypes defined by intraocular pressure (IOP) (≥22 or <22 mm Hg) or by visual field (VF) loss pattern at diagnosis (peripheral loss only or early paracentral loss). Cohort-specific and pooled multivariable rate ratios (MVRRs) and 95% CIs were estimated.

RESULTS

During 1 678 713 person-years of follow-up, 1483 incident cases of POAG were identified. The mean (SD) age for the 1483 cases was 66.8 (8.3). Compared with the lowest quintile of dietary nitrate intake (quintile 1: approximately 80 mg/d), the pooled MVRR for the highest quintile (quintile 5: approximately 240 mg/d) was 0.79 (95% CI, 0.66-0.93; P for trend = .02). The dose response was stronger (P for heterogeneity = .01) for POAG with early paracentral VF loss (433 cases; quintile 5 vs quintile 1 MVRR = 0.56; 95% CI, 0.40-0.79; P for trend < .001) than for POAG with peripheral VF loss only (835 cases; quintile 5 vs quintile 1 MVRR = 0.85; 95% CI, 0.68-1.06; P for trend = .50). The association did not differ (P for heterogeneity = .75) by POAG subtypes defined by IOP (997 case patients with IOP ≥22 mm Hg: quintile 5 vs quintile 1 MVRR = 0.82; 95% CI, 0.67-1.01; P for trend = .11; 486 case patients with IOP <22 mm Hg: quintile 5 vs quintile 1 MVRR = 0.71; 95% CI, 0.53-0.96; P for trend = .12). Green leafy vegetables accounted for 56.7% of nitrate intake variation. Compared with consuming 0.31 servings per day, the MVRR for consuming 1.45 or more servings per day was 0.82 for all POAG (95% CI, 0.69-0.97; P for trend = .02) and 0.52 for POAG with paracentral VF loss (95% CI, 0.29-0.96; P for trend < .001).

CONCLUSIONS AND RELEVANCE

Higher dietary nitrate and green leafy vegetable intake was associated with a lower POAG risk, particularly POAG with early paracentral VF loss at diagnosis.

Childhood cancer survivorship research in minority populations: A position paper from the Childhood Cancer Survivor Study

By the middle of this century, racial/ethnic minority populations will collectively constitute 50% of the US population. This temporal shift in the racial/ethnic composition of the US population demands a close look at the race/ethnicity-specific burden of morbidity and premature mortality among survivors of childhood cancer. To optimize targeted long-term follow-up care, it is essential to understand whether the burden of morbidity borne by survivors of childhood cancer differs by race/ethnicity. This is challenging because the number of minority participants is often limited in current childhood cancer survivorship research, resulting in a paucity of race/ethnicity-specific recommendations and/or interventions. Although the overall childhood cancer incidence increased between 1973 and 2003, the mortality rate declined; however, these changes did not differ appreciably by race/ethnicity. The authors speculated that any racial/ethnic differences in outcome are likely to be multifactorial, and drew on data from the Childhood Cancer Survivor Study to illustrate the various contributors (socioeconomic characteristics, health behaviors, and comorbidities) that could explain any observed differences in key treatment-related complications. Finally, the authors outlined challenges in conducting race/ethnicity-specific childhood cancer survivorship research, demonstrating that there are limited absolute numbers of children who are diagnosed and survive cancer in any one racial/ethnic minority population, thereby precluding a rigorous evaluation of adverse events among specific primary cancer diagnoses and treatment exposure groups. Cancer 2016;122:2426-2439. © 2016 American Cancer Society.

Pediatric hematology providers on referral for transplant evaluation for sickle cell disease: a regional perspective

Hematology referral for evaluation is a key step for hematopoietic stem cell transplantation for sickle cell disease (SCD). Pediatric SCD providers in the US Northeast (New York-Mid-Atlantic and New England regions) were surveyed anonymously for perspectives and practices regarding transplant referral and compared by whether they practiced at SCD transplant centers. Data were analyzed using the Fisher exact test, χ test, and logistic regression. Half of the respondents practiced primarily at transplant sites. Most (79%) were enthusiastic about transplant for SCD and 78% had recently referred ≥1 child for evaluation. Overall, 77% limited referral to certain sickle hemoglobinopathies and 44% preferred referral for β-thalassemia to SCD. Indications selected for referral resembled current transplant criteria, plus family request or poor response to therapy. Referral for children on chronic transfusions predicted enthusiasm and prior referral. Many (66%) referred children with multiple SCD complications, even without matched sibling donors, 37% with sibling donors despite limited disease. Practitioners at transplant centers more commonly accepted event-free survival rates of ≤90% (P=0.002). Northeastern providers expressed varying enthusiasm for referral for evaluation based on eligibility, donor availability, and acceptable risk, with modestly more interest from practitioners at transplant centers. Differing provider perspectives may affect patient referral for transplant consideration.

Relation between time spent outdoors and exfoliation glaucoma or exfoliation glaucoma suspect

PURPOSE

To evaluate the relation between time spent outdoors at various life periods and risk of exfoliation glaucoma or exfoliation glaucoma suspect.

DESIGN

Retrospective cohort study in the United States.

METHODS

Participants (49 033 women in the Nurses Health Study and 20 066 men in the Health Professionals Follow-up Study) were 60+ years old, were free of glaucoma and cataract, reported eye examinations, and completed questions about time spent outdoors in direct sunlight at midday at 3 life periods: high school to age 24 years, age 25-35 years, and age 36-59 years (asked in 2006 in women and 2008 in men). Participants were followed biennially with mailed questionnaires from 1980 women/1986 men to 2010. Incident cases (223 women and 38 men) were confirmed with medical records. Cohort-specific multivariable-adjusted rate ratios from Cox proportional hazards models were estimated and pooled with meta-analysis.

RESULTS

Although no association was observed with greater time spent outdoors in the ages of 25-35 or ages 36-59 years, the pooled multivariable-adjusted rate ratios for ≥11 hours per week spent outdoors in high school to age 24 years compared with ≤5 hours per week was 2.00 (95% confidence interval = 1.30, 3.08; P for linear trend = .001). In women, this association was stronger in those who resided in the southern geographic tier in young adulthood (P for interaction = .07).

CONCLUSIONS

Greater time spent outdoors in young adulthood was associated with risk of exfoliation glaucoma or exfoliation glaucoma suspect, supporting an etiologic role of early exposures to climatic factors.

A prospective study of folate, vitamin B₆, and vitamin B₁₂ intake in relation to exfoliation glaucoma or suspected exfoliation glaucoma

IMPORTANCE

Effective strategies for primary prevention are lacking for exfoliation glaucoma (EG), which is the most common type of secondary glaucoma.

OBJECTIVE

To examine the association between B vitamin intake and EG or suspected EG (EG/SEG) risk.

DESIGN, SETTING, AND PARTICIPANTS

National prospective cohort study using more than 20 years of follow-up data from the Nurses' Health Study (all female registered nurses) and the Health Professionals Follow-up Study (all male health professionals) from June 1, 1980, to May 31, 2010 (Nurses' Health Study) and January 1, 1986, to December 31, 2010 (Health Professionals Follow-up Study). We included a subset of 78,980 Nurses' Health Study women and 41,221 Health Professionals Follow-up Study men who were 40 years or older, free of glaucoma, had completed diet questionnaires, and reported eye examinations (follow-up rate, >85%).

EXPOSURES

Cumulatively updated intake of B vitamins (folate, vitamin B6, and vitamin B12) as ascertained by repeated administration of validated questionnaires.

MAIN OUTCOMES AND MEASURES

Incident cases of EG/SEG, totaling 399 (329 women and 70 men), were first identified with the questionnaires and were subsequently confirmed with medical records. Multivariable relative risks for EG/SEG were calculated in each cohort and then pooled with meta-analysis.

RESULTS

Vitamin B₆ and vitamin B₁₂ intake was not associated with EG/SEG risk in pooled analyses (P = .52 and P = .99 for linear trend, respectively). However, a suggestive trend of a reduced risk was observed with higher intake of folate: compared with the lowest quintile of cumulatively averaged updated total folate intake, the multivariable relative risk for EG/SEG for the highest quintile (≥654 μg/d) was 0.75 (95% CI, 0.54-1.04; P = .02 for linear trend). These results were not materially altered after adjustment for vitamin B₆ and vitamin B₁₂ intake. An association was observed for supplemental folate intake but not for dietary folate only (P = .03 and P = .64 for linear trend, respectively). Greater frequency of multivitamin use showed a modest suggestive inverse association (current multivitamin use of ≥6 times per week vs nonuse multivariable relative risk, 0.84; 95% CI, 0.64-1.11; P = .06 for linear trend).

CONCLUSIONS AND RELEVANCE

Higher total folate intake was associated with a suggestive lower risk for EG/SEG, supporting a possible causal role of homocysteine in EG/SEG.

Adding Postal Follow-Up to a Web-Based Survey of Primary Care and Gastroenterology Clinic Physician Chiefs Improved Response Rates but not Response Quality or Representativeness

This study assessed whether postal follow-up to a web-based physician survey improves response rates, response quality, and representativeness. We recruited primary care and gastroenterology chiefs at 125 Veterans Affairs medical facilities to complete a 10-min web-based survey on colorectal cancer screening and diagnostic practices in 2010. We compared response rates, response errors, and representativeness in the primary care and gastroenterology samples before and after adding postal follow-up. Adding postal follow-up increased response rates by 20-25 percentage points; markedly greater increases than predicted from a third e-mail reminder. In the gastroenterology sample, the mean number of response errors made by web responders (0.25) was significantly smaller than the mean number made by postal responders (2.18), and web responders provided significantly longer responses to open-ended questions. There were no significant differences in these outcomes in the primary care sample. Adequate representativeness was achieved before postal follow-up in both samples, as indicated by the lack of significant differences between web responders and the recruitment population on facility characteristics. We conclude adding postal follow-up to this web-based physician leader survey improved response rates but not response quality or representativeness.

A nested case control study of plasma ICAM-1, E-selectin and TNF receptor 2 levels, and incident primary open-angle glaucoma

PURPOSE

To evaluate prediagnostic markers of endothelial dysfunction and inflammatory processes in primary open-angle glaucoma (POAG).

METHODS

Blood samples were collected from 1989 to 1990 in the nurses' health study (women) and from 1993 to 1995 in the health professionals follow-up study (men), and medical-record confirmed incident poag cases were identified (women: 229 cases and 455 controls; men: 116 cases and 228 controls). Controls were matched on cohort, age, race, ethnicity, cancer status, and date of blood collection. Plasma concentrations of ICAM-1, E-selectin, and soluble TNF receptor 2 (sTNF-R2), a marker related to TNF-α, were measured with ELISA assays. Cohort-specific multivariable conditional logistic regression model results were meta-analyzed.

RESULTS

We observed no associations with ICAM-1 or E-selectin. for sTNF-R2, the mean (SD) plasma levels (pg/ml) in cases and controls were 2888 (997) and 2993 (913), respectively, in women; and 2622 (664) and 2569 (688), respectively, in men. pooled multivariable results showed no relation between sTNF-R2 levels and POAG. however, compared with the lowest tertile of sTNF-R2, the highest tertile showed a significant decreased risk of POAG in women (multivariable odds ratio [OR] = 0.58, 95% confidence interval [CI] = 0.360.93; P(trend) = 0.03) but not in men (P(trend) = 0.21; P for heterogeneity by sex = 0.03). also, among women, the inverse association with sTNF-R2 was stronger with normal-tension glaucoma (ntg; maximum intraocular pressure 21 mm Hg at diagnosis): highest versus lowest tertile comparison OR = 0.29 (95% CI = 0.12-0.71; Ptrend = 0.007).

CONCLUSIONS

In women, but not in men, higher sTNF-R2 levels at 6 to 8 years before diagnosis were inversely associated with POAG, but more strongly for NTG.

Exploring genome-wide - dietary heme iron intake interactions and the risk of type 2 diabetes

AIMS/HYPOTHESIS

Genome-wide association studies have identified over 50 new genetic loci for type 2 diabetes (T2D). Several studies conclude that higher dietary heme iron intake increases the risk of T2D. Therefore we assessed whether the relation between genetic loci and T2D is modified by dietary heme iron intake.

METHODS

We used Affymetrix Genome-Wide Human 6.0 array data [681,770 single nucleotide polymorphisms (SNPs)] and dietary information collected in the Health Professionals Follow-up Study (n = 725 cases; n = 1,273 controls) and the Nurses' Health Study (n = 1,081 cases; n = 1,692 controls). We assessed whether genome-wide SNPs or iron metabolism SNPs interacted with dietary heme iron intake in relation to T2D, testing for associations in each cohort separately and then meta-analyzing to pool the results. Finally, we created 1,000 synthetic pathways matched to an iron metabolism pathway on number of genes, and number of SNPs in each gene. We compared the iron metabolic pathway SNPs with these synthetic SNP assemblies in their relation to T2D to assess if the pathway as a whole interacts with dietary heme iron intake.

RESULTS

Using a genomic approach, we found no significant gene-environment interactions with dietary heme iron intake in relation to T2D at a Bonferroni corrected genome-wide significance level of 7.33 ×10(-) (8) (top SNP in pooled analysis: intergenic rs10980508; p = 1.03 × 10(-) (6)). Furthermore, no SNP in the iron metabolic pathway significantly interacted with dietary heme iron intake at a Bonferroni corrected significance level of 2.10 × 10(-) (4) (top SNP in pooled analysis: rs1805313; p = 1.14 × 10(-) (3)). Finally, neither the main genetic effects (pooled empirical p by SNP = 0.41), nor gene - dietary heme-iron interactions (pooled empirical p-value for the interactions = 0.72) were significant for the iron metabolic pathway as a whole.

CONCLUSIONS

We found no significant interactions between dietary heme iron intake and common SNPs in relation to T2D.

The Relationship between caffeine and coffee consumption and exfoliation glaucoma or glaucoma suspect: a prospective study in two cohorts

PURPOSE

We examined the association between caffeine and caffeinated beverage consumption in relation to the risk of exfoliation glaucoma or exfoliation glaucoma suspect (EG/EGS).

METHODS

We followed 78,977 women from the Nurses' Health Study (NHS) and 41,202 men from the Health Professionals Follow-up Study (HPFS) who were at least 40 years of age, did not have glaucoma, and reported undergoing eye examinations from 1980 (NHS) or 1986 (HPFS) to 2008. Information on consumption of caffeine-containing beverages and potential confounders were repeatedly ascertained in validated follow-up questionnaires. Confirmation with medical record review revealed 360 incident EG/EGS cases. Multivariate rate ratios (RRs) for EG/EGS were calculated in each cohort and then pooled using meta-analytic techniques.

RESULTS

Compared with participants whose cumulatively updated total caffeine consumption was <125 mg/day, participants who consumed ≥ 500 mg/day had a trend toward increased risk of EG/EGS that was not statistically significant (RR = 1.43; 95% confidence interval [CI], 0.98-2.08); P trend = 0.06). Compared to abstainers, those who drank ≥ 3 cups of caffeinated coffee daily were at increased risk of EG/EGS (RR = 1.66; 95% CI, 1.09-2.54; P trend = 0.02). These results were not materially altered after adjustment for total fluid intake. Associations were stronger among women with a family history of glaucoma (P interaction = 0.06 for coffee; P interaction = 0.03 for caffeine). We did not find associations with consumption of other caffeinated products (caffeinated soda, caffeinated tea, decaffeinated coffee or chocolate) and risk of EG/EGS (P trend ≥ 0.31).

CONCLUSIONS

We observed a positive association between heavier coffee consumption with risk of EG/EGS in this large prospective study.

Patient characteristics of provider survey respondents: no evidence of nonresponse bias

Surveys of physicians are an important tool to assess opinions and self-reported behaviors of this policy-relevant population. However, this population is notoriously difficult to survey and plagued with low and falling response rates. In order to evaluate the potential import of response rate, we examine the presence of nonresponse bias in a survey of physicians providing diabetes care that achieved a 36% response rate. Unlike other studies examining differences in individual characteristics for responding and nonresponding physicians, we also assess differences with respect to aggregate patient demographic, clinical, and behavioral characteristics. We are unable to demonstrate nonresponse bias, even with what could be construed as a relative low response rate. Nonetheless as the threat of nonresponse bias can never be completely assuaged, we believe that it should be monitored as a matter of course in physician surveys and offer a new dimension by which it can be evaluated.

Deployment of a mixed-mode data collection strategy does not reduce nonresponse bias in a general population health survey

OBJECTIVE

To assess nonresponse bias in a mixed-mode general population health survey.

DATA SOURCES

Secondary analysis of linked survey sample frame and administrative data, including demographic and health-related information.

STUDY DESIGN

The survey was administered by mail with telephone follow-up to nonrespondents after two mailings. To determine whether an additional mail contact or mode switch reduced nonresponse bias, we compared all respondents (N = 3,437) to respondents from each mailing and telephone respondents to the sample frame (N = 6,716).

PRINCIPAL FINDINGS

Switching modes did not minimize the under-representation of younger people, nonwhites, those with congestive heart failure, high users of office-based services, and low-utilizers of the emergency room but did reduce the over-representation of older adults.

CONCLUSIONS

Multiple contact and mixed-mode surveys may increase response rates, but they do not necessarily reduce nonresponse bias.

Effect of stamped reply envelopes and timing of newsletter delivery on response rates of mail survey: a randomised controlled trial in a prospective cohort study

OBJECTIVE

To examine the effects of stamped reply envelope and the timing of newsletter distribution.

DESIGN

A randomised controlled trial in a prospective cohort study with a 2×2 factorial design of two interventions.

SETTING

The Japan Nurses' Health Study (JNHS), a prospective cohort study for women's health.

PARTICIPANTS

The present study included 6938 women who were part of the first-year entry cohort for the fifth wave of the biannual follow-up survey of the JNHS.

INTERVENTION

The participants were randomly allocated into four groups; Group-1 (business-reply, newsletter with initial mailing), Group-2 (business-reply, newsletter with reminder), Group-3 (stamped envelopes, newsletter with initial mailing) and Group-4 (stamped envelopes, newsletter with reminder). The thank-you and reminder letters were mailed out at the end of the sixth week. This study was censored at the end of 12 weeks.

MAIN OUTCOME MEASURES

Main outcome measures were cumulative response at the end of 6 and 12 weeks after mailing out the questionnaire.

RESULTS

The cumulative response at 12 weeks were 58.3% for Group-1, 54.1% for Group-2, 60.5% for Group-3 and 56.7% for Group-4 (p=0.001). The odds of the response was higher for stamped envelopes than for business-reply envelopes (OR (95% CI)=1.10(1.00 to 1.21)). The odds was higher for newsletter delivery with initial mailing than for with reminder (1.18(1.07 to 1.29)). The response in first 6 weeks for stamped envelope was significantly higher than for business-reply envelope (p=0.047). Although the response in 6 weeks for women received the newsletter with initial mailing was lower than for women who did not, the proportions did not differ significantly (p=0.291).

CONCLUSIONS

The style of return envelope affected response rates of mail survey. The results of this study suggest that practices of provision of the additional information, should be handled individually in advance, as a separate event from sending follow-up questionnaire or reminder letters.

Gift card incentives and non-response bias in a survey of vaccine providers: the role of geographic and demographic factors

This study investigates the effects of non-response bias in a 2010 postal survey assessing experiences with H1N1 influenza vaccine administration among a diverse sample of providers (N = 765) in Washington state. Though we garnered a high response rate (80.9%) by using evidence-based survey design elements, including intensive follow-up and a gift card incentive from Target, non-response bias could exist if there were differences between respondents and non-respondents. We investigated differences between the two groups for seven variables: road distance to the nearest Target store, practice type, previous administration of vaccines, region, urbanicity, size of practice, and Vaccines for Children (VFC) program enrollment. We also examined the effect of non-response bias on survey estimates. Statistically significant differences between respondents and non-respondents were found for four variables: miles to the nearest Target store, type of medical practice, whether the practice routinely administered additional vaccines besides H1N1, and urbanicity. Practices were more likely to respond if they were from a small town or rural area (OR = 7.68, 95% CI = 1.44-40.88), were a non-traditional vaccine provider type (OR = 2.08, 95% CI = 1.06-4.08) or a pediatric provider type (OR = 4.03, 95% CI = 1.36-11.96), or administered additional vaccines besides H1N1 (OR = 1.80, 95% CI = 1.03-3.15). Of particular interest, for each ten mile increase in road distance from the nearest Target store, the likelihood of provider response decreased (OR = 0.73, 95% CI = 0.60-0.89). Of those variables associated with response, only small town or rural practice location was associated with a survey estimate of interest, suggesting that non-response bias had a minimal effect on survey estimates. These findings show that gift card incentives alongside survey design elements and follow-up can achieve high response rates. However, there is evidence that practices farther from the nearest place to redeem gift cards may be less likely to respond to the survey.

Reproductive factors and NOS3 variant interactions in primary open-angle glaucoma

PURPOSE

To investigate whether associations with the nitric oxide synthase gene (NOS3) variants and risk of primary open-angle glaucoma (POAG) depend on female reproductive factors.

METHODS

Two functional and two tagging single nucleotide polymorphisms (SNPs; T-786C: rs2070744, Glu298Asp: rs1799983, rs7830, and rs3918188) were evaluated in a nested case-control study from the Nurses' Health Study (women followed 1980 - 2002). Participants were aged ≥40 years and Caucasian, who were followed biennially with update information on reproductive factors. We included 374 Nurses' Health Study (NHS) cases and 1,085 controls, matched on age and eye exam at the matched cases' diagnosis dates. Relative risks (RRs) were estimated using multivariable conditional logistic regression.

RESULTS

Among women with age at menarche <13 years, compared with the CC homozygotes of the rs3918188 tagging SNP, the wild-type AA homozygotes were at significantly reduced risk of POAG (RR=0.31, 95% CI=0.16, 0.59); however, for women with age at menarche ≥13 years, the SNP was not associated with POAG (p-interaction=0.0007). Among parous women with 3+ children, carriers of the minor variant (T) allele of the functional Glu298Asp SNP were at increased risk, while among parous women with 1-2 children, they were not (p-interaction=0.003). No significant interactions between NOS3 SNPs and oral contraceptive use in POAG were detected.

CONCLUSIONS

These data provide further support for the notion that NOS3 genotype - female reproductive health interactions are important in POAG pathogenesis.

Endothelial nitric oxide synthase gene variants and primary open-angle glaucoma: interactions with hypertension, alcohol intake, and cigarette smoking

OBJECTIVE

To evaluate whether an association between risk of any of the factors of hypertension, alcohol intake, and cigarette smoking and the risk of primary open-angle glaucoma (POAG) depended on nitric oxide synthase 3 (NOS3) gene variants.

METHODS

Two functional single-nucleotide polymorphisms (SNPs) (T-786C [rs2070744] and Glu298Asp [rs1799983]) and 2 tagging SNPs (rs7830 and rs3918188) were evaluated in nested case-control studies from the Nurses' Health Study (1980-2002) and the Health Professionals' Follow-up Study (1986-2002). Participants were 40 years of age or older and white, and were followed up biennially. We included 527 incident case patients with POAG and 1539 control participants, matched by cohort, age, and eye examination at the matched case patients' diagnosis dates. Cohort-specific relative risks were estimated using multivariable conditional logistic regression and were pooled using meta-analytic methods.

RESULTS

The association between hypertension and POAG depended on T-786C SNP variants. Compared with TT homozygotes without hypertension, the TT homozygotes with hypertension were at significantly higher risk of POAG (relative risk,1.45 [95% confidence interval, 1.01-2.08]); however, among carriers of the variant (C) allele, hypertension was not associated with POAG (P interaction = .007). Similarly, compared with CC homozygotes with the rs7830 tagging SNP who never smoked, CC homozygotes who were past or current smokers were at significantly higher risk of POAG (relative risk, 1.63 [95% confidence interval, 1.15-2.31]); however, among carriers of the variant allele (A), smoking was not associated with POAG (P interaction = .004). Interactions were not observed with alcohol intake.

CONCLUSIONS

The associations between hypertension and cigarette smoking in relation to POAG depended on NOS3 SNPs.

Surveying Nurses

While surveys of nurses are an important tool in health services and policy research, they are often characterized by low response rates. The authors conducted a systematic review of 22 published reports of efforts to improve response rates to nurse surveys. Two general strategies were explored in this literature: incentive and design-based approaches. Even small financial incentives were found to be effective in improving nurse survey participation. Token nonmonetary incentives, in contrast, were much less effective. In terms of design strategies, postal and telephone strategies have generally been more successful than have fax or web-based approaches, with evidence also supporting use of mixed-mode surveys in this population. In addition, use of first-class stamps on return envelopes as well as questionnaires personalized and endorsed by legitimizing professional associations were also more likely to be successful. Researchers should continue to implement evidence-based strategies in order to improve the survey response of nurses.

Circulating carotenoids, mammographic density, and subsequent risk of breast cancer

Mammographic density is one of the strongest predictors of breast cancer risk. Recently, it has been suggested that reactive oxygen species may influence breast cancer risk through its influence on mammographic density. In the current study, we addressed this hypothesis and also assessed if the association between carotenoids and breast cancer risk varies by mammographic density. We conducted a nested case-control study consisting of 604 breast cancer cases and 626 controls with prospectively measured circulating carotenoid levels and mammographic density in the Nurses' Health Study. Circulating levels of alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein/zeaxanthin were measured. We used a computer-assisted thresholding method to measure percent mammographic density. We found no evidence that circulating carotenoids are inversely associated with mammographic density. However, mammographic density significantly modified the association between total circulating carotenoids and breast cancer (P heterogeneity = 0.008). Overall, circulating total carotenoids were inversely associated with breast cancer risk (P trend = 0.01). Among women in the highest tertile of mammographic density, total carotenoids were associated with a 50% reduction in breast cancer risk (odds ratio, 0.5; 95% confidence interval, 0.3-0.8). In contrast, there was no inverse association between carotenoids and breast cancer risk among women with low mammographic density. Similarly, among women in the highest tertile of mammographic density, high levels of circulating alpha-carotene, beta-cryptoxanthin, lycopene, and lutein/zeaxanthin were associated with a significant 40% to 50% reduction in breast cancer risk (P trend < 0.05). Our results suggest that plasma levels of carotenoids may play a role in reducing breast cancer risk, particularly among women with high mammographic density.

Predictors of nonresponse in a questionnaire-based outcome study of vocational rehabilitation patients

OBJECTIVE

To identify predictors of nonresponse to a self-report study of patients with orthopedic trauma hospitalized for vocational rehabilitation between November 15, 2003, and December 31, 2005. The role of biopsychosocial complexity, assessed using the INTERMED, was of particular interest.

DESIGN

Cohort study. Questionnaires with quality of life, sociodemographic, and job-related questions were given to patients at hospitalization and 1 year after discharge. Sociodemographic data, biopsychosocial complexity, and presence of comorbidity were available at hospitalization (baseline) for all eligible patients. Logistic regression models were used to test a number of baseline variables as potential predictors of nonresponse to the questionnaires at each of the 2 time points.

SETTING

Rehabilitation clinic.

PARTICIPANTS

Patients (N=990) hospitalized for vocational rehabilitation over a period of 2 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Nonresponse to the questionnaires was the binary dependent variable.

RESULTS

Patients with high biopsychosocial complexity, foreign native language, or low educational level were less likely to respond at both time points. Younger patients were less likely to respond at 1 year. Those living in a stable partnership were less likely than singles to respond at hospitalization. Sex, psychiatric, and somatic comorbidity and alcoholism were never associated with nonresponse.

CONCLUSIONS

We stress the importance of assessing biopsychosocial complexity to predict nonresponse. Furthermore, the factors we found to be predictive of nonresponse are also known to influence treatment outcome and vocational rehabilitation. Therefore, it is important to increase the response rate of the groups of concern in order to reduce selection bias in epidemiologic investigations.

Endothelial nitric oxide synthase gene variants and primary open-angle glaucoma: interactions with sex and postmenopausal hormone use

PURPOSE

To evaluate the association between the nitric oxide synthase gene (NOS3) variants and primary open-angle glaucoma (POAG).

METHODS

Two functional single-nucleotide polymorphisms (SNPs) (T-786C: rs2070744; Glu298Asp: rs1799983) and three tagging SNPs (rs7830, rs3918188, and rs1800779) were evaluated in a nested case-control study from the Nurses' Health Study (1980-2002) and the Health Professionals' Follow-up Study (1986-2002). Participants were aged >or=40 years and Caucasian. Included were 527 incident cases and 1543 controls, matched by cohort, age, and eye examination at the matched cases' diagnosis dates. Cohort-specific relative risks (RR) were estimated by using multivariable conditional logistic regression and were pooled with meta-analysis.

RESULTS

No NOS3 polymorphism was significantly associated with overall POAG. For high-tension POAG (HTPOAG), rs3918188 was significantly inversely associated among the women (AA versus CC genotype: RR = 0.48; 95% CI, 0.28-0.82) but not among the men (P-heterogeneity by sex = 0.02). The minor alleles of T -786C and rs1800779 showed positive association with high-tension POAG (P-trend < 0.02) in the women only, but P-heterogeneity was not significant. In the women, four of the five NOS3 SNPs showed significant interactions with postmenopausal hormone (PMH) use in relation to HTPOAG: for example, among the women with the TT genotype in T -786C, PMH use was inversely associated (RR = 0.41; 95% CI, 0.22-0.76), but among carriers of the minor allele, use of PMH was not associated.

CONCLUSIONS

Interactions were observed between NOS3 SNPs and female sex and postmenopausal hormone use in the women in relation to HTPOAG. These findings should be confirmed in different racial/ethnic groups.

Smoking trends in the Nurses' Health Study (1976-2003)

BACKGROUND

Smoking trends among nurses are important to monitor as smoking negatively affects their health and decreases their likelihood of providing cessation interventions to patients.

OBJECTIVES

The objective of the study was to describe the changes in smoking trends in the participants in the Nurses' Health Study (NHS) cohorts over 27 years.

METHODS

An analysis of biennial changes in smoking status and cigarette consumption within nine 5-year birth cohorts (1920-1924 to 1960-1964) and age-specific mortality rates by smoking status were examined in 237,648 female registered nurses (RNs): NHS (ages of 30-55 years in 1976, followed through 2002) and NHS II (ages of 25-42 years in 1989, followed through 2003).

RESULTS

Current smokers constituted 33.2% of NHS in 1976 and 13.5% of NHS II in 1989. Smoking rates declined in all birth cohorts; 8.4% were smoking in 2002/2003. Seventy-nine percent of nurses who ever smoked had quit. The mean cigarettes per day declined over time but still exceeded half a pack per day (15.1 cigarettes) at the end of follow-up. The mortality rate among current smokers was higher than that of former smokers and was approximately twice that of never smokers in all age categories; those who smoked were more likely to have comorbid conditions.

DISCUSSION

This study provides the first report of smoking trends among RNs in the NHS. The decline in smoking rate among female nurses mirrors the decline in smoking rate among women in the United States over the past 25 years. Increased mortality and morbidity rates indicate the devastating cost of smoking to the profession and can provide support for the urgent need for further research to encourage continued smoking cessation efforts for nursing professionals.

Caffeine consumption and the risk of primary open-angle glaucoma: a prospective cohort study

PURPOSE

To investigate whether caffeine, which transiently increases intraocular pressure (IOP) is associated with the risk of primary open-angle glaucoma (POAG).

METHODS

A total of 79,120 women from 1980 to 2004 and 42,052 men from 1986 to 2004, who were 40+ years of age, did not have POAG, and reported undergoing eye examinations, were observed. Information on caffeine consumption, potential confounders, and POAG diagnoses were repeatedly updated in validated follow-up questionnaires. One thousand eleven incident POAG cases were confirmed with medical record review. Cohort-specific and pooled analyses across cohorts were conducted to calculate multivariate rate ratios (RRs).

RESULTS

Compared with daily intake of less than 150 mg, the pooled multivariate RRs were 1.05 (95% confidence interval [CI], 0.89-1.25) for consumption of 150 to 299 mg/d, 1.19 (95% CI, 0.99-1.43) for 300 to 449 mg/d, 1.13 (95% CI, 0.89-1.43) for 450 to 559 mg/d, and 1.17 (95% CI, 0.90-1.53) for 600+ mg/d (P for trend = 0.11). However, for consumption of five or more cups of caffeinated coffee daily, the RR was 1.61 (95% CI, 1.00-2.59; P for trend = 0.02); tea or caffeinated cola intake were not associated with risk. Greater caffeine intake was more adversely associated with POAG among those reporting a family history of glaucoma, particularly in relation to POAG with elevated IOP (P for trend = 0.0009; P interaction = 0.04).

CONCLUSIONS

Overall caffeine intake was not associated with increased risk of POAG. However, in secondary analyses, caffeine appeared to elevate risk of high-tension POAG among those with a family history of glaucoma. This result may be due to chance, but warrants further study.

An Examination of the Convergent and Discriminant Validity of the Strengths and Difficulties Questionnaire

This study examined the factor structure of the parent and teacher versions of the Strengths and Difficulties Questionnaire (SDQ; R. Goodman, 1997) with a sample of first-grade children at risk for educational failure. The 5-factor model previously found in studies using exploratory factor analysis was fit to the data for both parent and teacher questionnaires. Fit indices for both versions were marginally adequate. Model fit was comparable across gender and ethnic groups. Factor fit for the parent questionnaire was invariant across parent educational level. The examination of convergent and discriminant validity included peer evaluations of each SDQ construct. Thus, each of the five constructs was evaluated by three sources (parent, teacher, and child). On the basis of D. T. Campbell and D. W. Fiske's (1959) multitrait-multimethod approach as well as a confirmatory factor analysis using the correlated uniqueness model, the SDQ has good convergent validity but relatively poor discriminant validity.

Endogenous hormone levels, mammographic density, and subsequent risk of breast cancer in postmenopausal women

BACKGROUND

Mammographic density and circulating sex hormones are two well-confirmed predictors of breast cancer risk. Whether mammographic density reflects levels of endogenous sex hormones is unclear. We examined whether these predictors are independently associated with breast cancer risk in a prospective study.

METHODS

We conducted a nested case-control study within the Nurses' Health Study cohort of 253 case subjects with breast cancer and 520 control subjects. All participants were postmenopausal women who were not using postmenopausal hormones at the time of both blood collection and mammography. Plasma levels of estradiol, free estradiol, testosterone, and free testosterone were evaluated. Mammographic density was assessed by use of computer-assisted analysis of mammograms. Logistic regression models that were adjusted for matching variables and potential confounders were used to calculate relative risks (RRs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

Levels of circulating sex steroids and mammographic density were both statistically significantly and independently associated with breast cancer risk. The relative risk of breast cancer associated with mammographic density (RR for highest quartile compared with lowest quartile = 3.8, 95% CI = 2.2 to 6.6; P(trend)<.001) changed little when the analysis was adjusted for circulating estradiol (RR = 3.9, 95% CI = 2.2 to 6.9; P(trend)<.001) or circulating testosterone (RR = 4.1, 95% CI = 2.3 to 7.2; P(trend)<.001). Circulating levels of estradiol (RR = 2.4, 95% CI = 1.4 to 4.0) and of testosterone (RR = 2.0, 95% CI = 1.2 to 3.1) were both associated with breast cancer risk, before and after adjustment for mammographic density. In a joint analysis of mammographic density and plasma testosterone, the risk of breast cancer was highest in the highest tertiles of both relative to the lowest tertiles of both (RR = 6.0, 95% CI = 2.6 to 14.0). A similar pattern was observed in the joint analysis of estradiol and mammographic density (RR = 4.1, 95% CI = 1.7 to 9.8).

CONCLUSIONS

Circulating sex steroid levels and mammographic density appear strongly and independently associated with the risk of breast cancer in postmenopausal women.

Mixed-mode administration reduced bias and enhanced poststratification adjustments in a health behavior survey

OBJECTIVE

To assess whether a mixed-mode survey design reduced bias and enhanced methods commonly used to correct for bias (poststratification weighting).

STUDY DESIGN AND SETTING

The data for this paper are from a study of 1,900 adult patients enrolled in a randomized controlled trial to promote repeat treatment for relapsed smokers at five Veteran's Affairs Medical Centers. A sequential mixed-mode design was used for data collection whereby the initial attempt was conducted using phone administration, with mail follow-up for nonresponders. Analyses examined demographic, health, and smoking cessation treatment seeking differences between telephone responders, mail responders, and nonresponders and compared the relative effectiveness of global vs. targeted poststratification weighting adjustments for correcting for response bias.

RESULTS

The findings suggest (1) that responders to the additional survey mode (mail) did not significantly differ from responders to the first mode (phone) or nonresponders and (2) that poststratification weighting adjustments that take this additional information into account perform better than the standard global adjustments.

CONCLUSIONS

A mixed-mode design can improve survey representativeness and enhance the performance of poststratification weighting adjustments.

Nonresponse bias in a mail survey of physicians

With the increased pressure on survey researchers to achieve high response rates, it is critical to explore issues related to nonresponse. In this study, the authors examined the effects of nonresponse bias in a mail survey of physicians (N = 3,400). Because slightly more than one half of the sample did not respond to the survey, there was potential for bias if nonresponders differed significantly from responders with respect to key demographic and practice variables. They analyzed response status and timing of response with respect to five variables: gender, region, specialty, urbanicity, and survey length. The potential consequences of nonresponse bias on the survey estimates were then analyzed. Men were more likely to respond, as were physicians receiving a shorter questionnaire. Repeated follow-up attempts reduced gender response bias because male physicians were more likely to be early responders. Overall, higher response rates were not associated with lower response bias.

Does low participation in cohort studies induce bias?

BACKGROUND

Participation rates in large cohort studies have decreased during the last 2 decades. The consequences of this trend for relative risk estimation are unknown.

METHODS

The impact of a low participation rate (30%) on the Danish National Birth Cohort was examined among 49,751 women from the source population, including 15,373 participants in the cohort study. On the basis of independent data collection, we estimated odds ratios (ORs) in the source population and among participants for 3 exposure-risk associations: (a) in vitro fertilization and preterm birth, (b) smoking during pregnancy and birth of a small-for-gestational-age infant, and (c) prepregnancy body mass index and antepartum stillbirth. The effect of nonparticipation was described by a relative odds ratio (ROR), calculated as the OR(participants)/OR(source population). Two methods for calculation of confidence intervals for the relative odds ratio also were assessed.

RESULTS

The effect of nonparticipation on the selected ORs was small. The relative ORs were close to one and the bias was never larger than 16%, although some of the confidence intervals were wide. The 2 methods for calculation of confidence intervals gave very similar results and a small simulation study showed that the coverage probabilities were close to the 95% nominal level.

CONCLUSION

For the 3 chosen associations, the ORs were not biased by nonparticipation. The results are reassuring for studies based on the Danish cohort and similar cohorts of pregnant women. The methodology used to compute confidence intervals for the relative odds ratios performed well in the scenarios considered.

Generalizability of Relative Risk Estimates from a Well-defined Population to a General Population

We investigated the degree of generalizability of relative risk (RR) estimates for a sample from a well-defined population to a general population using actual data. A total of 45,452 men aged 40-69 years who completed a self-administered questionnaire were followed from 1990-1994 to the end of 1999-2000 in the Japan Public Health Center-based Prospective Study. We considered those who responded to the self-administered questionnaire (45,452 men) as representing the general population (population), and those who underwent a health check-up as representing a sample from a well- defined population (sample) (12,162 men). Exposure distributions, mortality rates, and the confounder-adjusted RRs of all-cause mortality according to cigarette smoking or body mass index (BMI) were compared between the sample and the population using empirical sampling distributions from the population. The sample had significantly different prevalences of exposures and lower mortality rates than the population. Adjusted RRs were significantly higher in current smokers (RR = 1.83) and in subjects who smoked > or =40 cigarettes per day (RR = 2.67) in the sample than the respective values in the corresponding categories (RR = 1.48 and 1.62, respectively) of the population. The adjusted RR of those with the lowest BMI in the sample (RR = 1.30) were also significantly lower than those of the corresponding category in the population (RR = 2.06). Our results suggest that even for RRs, the extrapolation of estimates for a sample from a well-defined population to a general population may not be possible.

Attrition in a population-based cohort eight years after baseline interview: The Cornella Health Interview Survey Follow-up (CHIS.FU) Study

PURPOSE

To examine how response at follow-up varied from baseline sociodemographic data in a Spanish population-based cohort after 8 years of follow-up.

METHODS

The Cornella Health Interview Survey Follow-up (CHIS.FU) Study is a population-based cohort study on lifestyle risk factors and their consequences on health status with 2500 participants at baseline. We have compared the distribution of baseline characteristics according to the results at follow-up (interview, decease, migration, or refusal).

RESULTS

Almost two-thirds of the subjects who did not respond to the follow-up interview had died or moved to another town. Sex was a determinant of attrition in deceased and non-traced participants. Refusal appeared to be associated with working status and place of birth. Self-perceived health was one of the characteristics associated with mortality; subjects who perceived their health as poor were 2.6 times more likely to die than those who felt they were in good health. Disabled and retired subjects together with housewives showed a higher risk of dying than individuals still working. The determinants of attrition among emigrated subjects were civil status, age, level of studies, working status, and birth place.

CONCLUSION

Although the attrition was non-random, there was no serious bias in estimates of change and in determinants of change due to attrition.

Response rates and response bias for 50 surveys of pediatricians

RESEARCH OBJECTIVE

To track response rates across time for surveys of pediatricians, to explore whether response bias is present for these surveys, and to examine whether response bias increases with lower response rates.

DATA SOURCE/STUDY SETTING

A total of 63,473 cases were gathered from 50 different surveys of pediatricians conducted by the American Academy of Pediatrics (AAP) since 1994. Thirty-one surveys targeted active U.S. members of the AAP, six targeted pediatric residents, and the remaining 13 targeted AAP-member and nonmember pediatric subspecialists. Information for the full target samples, including nonrespondents, was collected using administrative databases of the AAP and the American Board of Pediatrics.

STUDY DESIGN

To assess bias for each survey, age, gender, location, and AAP membership type were compared for respondents and the full target sample. Correlational analyses were conducted to examine whether surveys with lower response rates had increasing levels of response bias.

PRINCIPAL FINDINGS

Response rates to the 50 surveys examined declined significantly across survey years (1994-2002). Response rates ranged from 52 to 81 percent with an average of 68 percent. Comparisons between respondents and the full target samples showed the respondent group to be younger, to have more females, and to have less specialty-fellow members. Response bias was not apparent for pediatricians' geographical location. The average response bias, however, was fairly small for all factors: age (0.45 years younger), gender (1.4 percentage points more females), and membership type (1.1 percentage points fewer specialty-fellow members). Gender response bias was found to be inversely associated with survey response rates (r=-0.38). Even for the surveys with the lowest response rates, amount of response bias never exceeded 5 percentage points for gender, 3 years for age, or 3 percent for membership type.

CONCLUSIONS

While response biases favoring women, young physicians, and nonspecialty-fellow members were found across the 52-81 percent response rates examined in this study, the amount of bias was minimal for these factors that could be tested. At least for surveys of pediatricians, more attention should be devoted by investigators to assessments of response bias rather than relying on response rates as a proxy of response bias.

Response patterns to a postal survey using a cervical screening register as the sampling frame

This study compared different types of respondent to a postal survey. A random sample of women aged 20-64 years (n = 4057) was selected from a population-based cervical screening register to examine their information experience during the screening programme. The initial response rate was 57%, and this increased to 81% after one reminder. Respondents were older (P < 0.0001) than non-respondents, but both groups were comparable with regard to attendance history for cervical screening (respondents 89.3%; non-respondents 89.1%) and normal smear test results (respondents 84.0%; non-respondents 81.4%). Early and late respondents were similar in age. Compared with late respondents, early respondents were more likely to live in highly affluent (P < 0.0001) and rural areas (P = 0.026). They were also more likely to be non-attenders (P < 0.0001), but they were less likely to have had inadequate smear results (P = 0.030) than late respondents. These results suggest that consideration should be given to factors other than sociodemographic differences when examining response patterns to postal surveys.

Participation bias in a population-based echocardiography study

PURPOSE

To compare the characteristics of participants and non-participants in a population-based study of cardiac ventricular function.

METHODS

Subjects aged 45 years and older on January 1, 1997 were recruited from a sampling frame of Olmsted County residents from the Rochester Epidemiology Project. Subjects were asked to complete a 17-page questionnaire and participate in a 4-hour clinical examination that included a brief physical examination, echocardiography, spirometry, and an electrocardiogram. With specific IRB approval, the community medical records of participants and non-participants from the first wave of recruitment were examined by trained nurse abstractors to elicit details of past medical history.

RESULTS

Of the first 963 persons invited to participate in the study, 488 (51%) completed all phases of the examination. Participation rates were similar among men and women (53% vs. 49%, respectively). By age, participation rates were lowest among persons aged 75 years and older (44.7% and 34.9%) and 45 to 54 years (45.4% and 44.3%) for men and women. Participation rates were not different according to past history of coronary heart disease, congestive heart failure, or other cardiovascular disease. Persons with a history of chronic obstructive pulmonary disease were less likely to participate (19.4% vs. 51%; odds ratio, 0.36; 95% confidence interval, 0.18, 0.76) after adjustment for age, sex, and comorbid conditions.

CONCLUSIONS

These results provide some reassurance that participation bias in this study may have little influence on its overall findings, although this cannot be conclusive.

Validation of a home safety questionnaire used in a randomised controlled trial

OBJECTIVE

To measure the validity of self reported safety practices from a questionnaire, completed by families participating in a home safety randomised controlled trial.

METHODS

The postal questionnaire was used to measure secondary outcomes in a randomised controlled trial. The answers to 26 questions that could be assessed by observation were checked by a home visit. Families were invited to take part in a "home safety check"; they were not told that the visit was part of a validation study. At the time of the visit the researcher was blind to the self reports in the questionnaires.

RESULTS

Sixty four questionnaires were validated by visits to 64 households. Percentage agreement ranged from 58% to 100%. Sensitivity was high (68% or above) for most safety practices. The positive predictive value was also high for most safety practices (78% or above for 15 of the 16 practices).

CONCLUSIONS

This study found a fairly high degree of consistency between self reported data and actual observations. The findings from this relatively small study need confirmation from larger studies.