Comparison of telephone sampling and area sampling: response rates and within-household coverage

Theory, methods, and operational results of the Young Women's Health History Study: a study of young-onset breast cancer incidence in Black and White women

Purpose

The etiology of young-onset breast cancer (BC) is poorly understood, despite its greater likelihood of being hormone receptor-negative with a worse prognosis and persistent racial and socioeconomic inequities. We conducted a population-based case–control study of BC among young Black and White women and here discuss the theory that informed our study, exposures collected, study methods, and operational results.

Methods

Cases were non-Hispanic Black (NHB) and White (NHW) women age 20–49 years with invasive BC in metropolitan Detroit and Los Angeles County SEER registries 2010–2015. Controls were identified through area-based sampling from the U.S. census and frequency matched to cases on study site, race, and age. An eco-social theory of health informed life-course exposures collected from in-person interviews, including socioeconomic, reproductive, and energy balance factors. Measured anthropometry, blood (or saliva), and among cases SEER tumor characteristics and tumor tissue (from a subset of cases) were also collected.

Results

Of 5,309 identified potentially eligible cases, 2,720 sampled participants were screened and 1,812 completed interviews (682 NHB, 1140 NHW; response rate (RR): 60%). Of 24,612 sampled control households 18,612 were rostered, 2,716 participants were sampled and screened, and 1,381 completed interviews (665 NHB, 716 NHW; RR: 53%). Ninety-nine% of participants completed the main interview, 82% provided blood or saliva (75% blood only), and SEER tumor characteristics (including ER, PR and HER2 status) were obtained from 96% of cases.

Conclusions

Results from the successfully established YWHHS should expand our understanding of young-onset BC etiology overall and by tumor type and identify sources of racial and socioeconomic inequities in BC.

Supplementary Information

The online version of this article contains supplementary material available (10.1007/s10552-021-01461-x).

Can respondent driven sampling be used to recruit new mothers? A mixed methods study in metropolitan Washington DC

Background

Respondent driven sampling (RDS) is employed to recruit populations that are hard-to-reach, “hidden,” or without a sampling frame. For new mothers (those with infants <6 months) in countries without national health care systems or registries, there is no sampling frame, and random samples may only be attained through costly strategies, e.g., random-dial calling.

Objective

To assess the feasibility of RDS to recruit new mothers.

Methods

In the initial study, we recruited 30 new mothers (“seeds”) from a single birth hospital; each was given 3 referral coupons to give to other mothers (“referrals”). When our sample did not self-perpetuate with referrals, additional seeds were recruited. Demographics of seeds and referrals were compared. A subset of mothers participated in focus groups and were asked about their experience with RDS. We also conducted a second survey of new mothers to further assess feasibility of RDS in this population.

Results

Of the 402 mothers recruited in the initial study, 305 were seeds and only 97 were referrals. Referrals were more likely to be White, highly educated, older, and privately insured (all p≤0.001). Focus group participants indicated that the time required to meet other mothers was an important barrier. In the second survey we recruited 201 mothers; only 53.7% knew ≥1 mother whom they could invite to the study.

Conclusions

New mothers are not easily recruited using RDS because they have a limited number of contacts who are also new mothers. Those recruited through RDS are more likely to be older, Caucasian and of high socioeconomic status, indicating it is not an effective way to recruit a representative sample of new mothers.

Cost-efficient case-control cluster sampling designs for population-based epidemiological studies

Cost-efficient sampling schemes for population-based case-control studies are necessary for sampling subjects in geographically dispersed populations where in-house surveys are expensive to conduct due to high interviewer travel costs that may be associated with simple random sampling. Motivated by the original study conducted by Cockburn et al. (2011) that investigated the relationship between exposure to pesticides and prostate carcinogenesis, a set of cluster-based individually matched case-control designs is presented for cost-efficient sampling of additional controls. Based on cluster sampling from the field of survey sampling, the case-control study designs presented, where one case is individually matched to three controls, use case-control status in the sampling of the primary sampling clusters. In the secondary stage, interviewer travel costs are reduced by subsampling additional controls within primary sampling clusters as opposed to selecting additional controls purely at random, which would be highly inefficient from a cost perspective. Compared to the simple random sampling (SRS) 1:1 and SRS 1:3 (one case matched to: n SRS control(s)) designs, computer simulations demonstrate that these cluster-based designs provide unbiased rate ratio estimation and statistical efficiencies that are no worse than the SRS 1:1 design and moderately less than the SRS 1:3 design. Even under situations where the intracluster correlation for the exposure variable is extremely high for the exposure of interest, the cluster-based designs have statistical efficiencies that are comparable to that of the SRS 1:1 design. Furthermore, a cost-efficiency analysis is presented that demonstrates that the cluster-based designs are more cost-efficient compared to the SRS 1:3 design.

Falls and injuries to Polo players: risk perception, mitigation and risk factors

Polo, one of the world’s oldest sports, is played in over 80 countries. It is unique in combining the skills of a person with the agility and performance of an animal in a contact sport. There is only one report of the frequency and type of injuries in this population. Here we report risk perception, mitigation and risk factors for injuries and falls in UK polo players. Data were collected retrospectively from a random sample of 112 UK polo players by telephone questionnaire. Injuries (commonly to a shoulder or wrist) requiring a hospital visit were sustained by 17.3% (95% confidence interval [CI] 9.1–25.5) of players. Falls (odds ratio [OR] 6.6, 95% CI 1.4–31.9) and higher self-assessed fitness levels increased the risk (OR 1.7, CI 1.2–2.4). Use of wrist supports (OR 0.2, CI 0.03–0.9) and gym exercise (OR 0.1, CI 0.02–0.9) reduced it. Falls were reported by 58% (CI 47.3–68.8) of players. Women were less at risk than men (OR 0.3, CI 0.1–0.9). Aiming for a better handicap increased the risk (OR 8.4, CI 1.2–57.0). Pre-season rider and horse training were also risk factors. Helmets are compulsory, but players reported that safety certification was not their most important criterion for helmet selection; 49.4% (CI 38.5–60.3) chose appearance. Attendance of a doctor at polo games was not considered important by 65.4% (CI 55.1–75.8) of players; attendance of paramedics and ambulances was volunteered as being of greater consequence. The findings of this study suggest that the protective effect of wrist supports needs testing, helmet manufacturers should incorporate both style and safety into their designs, and paramedics and ambulances should attend polo games.

Strategies for recruiting representative samples of Asian Americans for a population-based case-control study

BACKGROUND

Data are limited on effective methods for recruiting persons, especially from ethnically diverse populations, into population-based studies. The goal of this study was to evaluate the variation among and representativeness of controls identified using multiple methods for a population-based case-control study of breast cancer among Asian Americans, Native Hawaiians and Pacific Islanders (AANHPIs) in the San Francisco Bay Area.

METHODS

We used a unique combination of targeted recruitment strategies, including address-based sampling, community-based methods, and internet-based and media-based approaches for recruiting controls, frequency matched on age and ethnicity to a population-based sample of cases. To characterise the participating controls, we compared the distribution of sociodemographic characteristics and cancer risk factors between recruitment sources using χ(2) tests. To ensure that the controls we recruited were representative of the underlying at-risk population, we compared characteristics of the controls, by ethnicity and in aggregate, to data from the California Health Interview Survey (CHIS), and adjusted the relative mix of recruitment strategies throughout the study as needed to achieve representativeness.

RESULTS

As expected, controls (n=483) recruited by any single method were not representative. However, when aggregated across methods, controls were largely representative of the underlying source population, as characterised by CHIS, with regard to the characteristics under study, including nativity, education, marital status and body mass index.

CONCLUSIONS

A multimode approach using targeted recruitment strategies is an effective and feasible alternative to using a single recruitment method in identifying a representative, diverse control sample for population-based studies.

Polo pony injuries: player-owner reported risk, perception, mitigation and risk factors

REASONS FOR PERFORMING STUDY

Polo, one of the world's oldest sports, is unique in merging human skill and balance with animal agility and performance in a contact sport. These modern-day 'centaurs' offer medical, dental and veterinary scientists an unrivalled, if quirky, opportunity to collaborate. Collection of epidemiological data on injuries to UK polo riders and ponies is the first step.

OBJECTIVES

To measure the reported risk and risk factors for injuries to UK polo ponies, their perception and mitigation by player-owners.

STUDY DESIGN

A retrospective cohort design and telephone interviews were used.

METHODS

Data on equine injuries, preseason training and risk perception were collected from a random sample of player-owners using a structured questionnaire. Injuries were defined as requiring veterinary treatment. Frequencies were represented as percentages and 95% confidence intervals (CIs). Risk factors for injuries were identified by univariable and multivariable analyses.

RESULTS

The cumulative incidence of player-owner-reported injury was 10.6% (95% CI 8.4-12.7). Tendon injuries were most common (4.3%; 95% CI 2.9-5.7), followed by wounds and splints. The only risk factor was stabling all season (odds ratio 4.79; 95% CI 1.46-15.73). Tendon injuries were perceived as the major risk and hard ground the most important risk factor. Risk mitigation practices were bandaging before exercise (45.7%; 95% CI 34.8-56.5), checking tendons (84.0%; 95% CI 76.0-91.9), cold hosing (40.7%; 95% CI 30.0-51.4), bandaging (38.3%; 95% CI 27.7-48.9) and using clays and coolants after exercise (24.7%; 15.3-34.1). Cuts and wounds were considered most frequent by only 2.5% (95% CI 0.0-3.6) of players but were the second most common injury, accounting for 21.6% of veterinary treatments. Splints accounted for 12.5% of injuries.

CONCLUSIONS

The risk of injury to polo ponies is similar to that in the general horse population; musculoskeletal injuries, particularly tendon injuries, are most common, followed by wounds and splints. The association between stabling and injury, risk factors for wounds and splints and efficacy of cooling tendons post exercise warrant further study.

Selection of neighborhood controls for a population-based Lyme disease case-control study by using a commercial marketing database

The selection of controls is an important methodological consideration for case-control studies. Neighborhood-matched control selection is particularly crucial for studies of vector-borne disease, such as Lyme disease, for which risk is intrinsically linked to geographical location. The matching of case-control pairs on neighborhood can help control for variation in ecological risk factors that are tied to geographical location, like vector and host habitat in the peridomestic environment. Random-digit dialing has been used to find neighborhood controls by using the area code and exchange of the case to generate lists of potential control households. An alternative to random-digit dialing is the purchase of residential telephone numbers from a commercial marketing database. This report describes the utility of the InfoUSA.com (InfoGroup, Papillion, Nebraska) commercial marketing database for neighborhood control recruitment in a Lyme disease case-control study in Connecticut during 2005-2007.

Rethinking sources of representative controls for the conduct of case-control studies in minority populations

BACKGROUND

Recruitment of controls remains a challenge in case-control studies and particularly in studies involving minority populations.

METHODS

We compared characteristics of controls recruited through random digit dialing (RDD) to those of community controls enrolled through churches, health events and other outreach sources among women of African ancestry (AA) participating in the Women's Circle of Health Study, a case-control study of breast cancer. Odds ratios and 95% confidence intervals were also computed using unconditional logistic regression to evaluate the impact of including the community controls for selected variables relevant to breast cancer and for which there were significant differences in distribution between the two control groups.

RESULTS

Compared to community controls (n=347), RDD controls (n=207) had more years of education and higher income, lower body mass index, were more likely to have private insurance, and less likely to be single. While the percentage of nulliparous women in the two groups was similar, community controls tended to have more children, have their first child at a younger age, and were less likely to breastfeed their children. Dietary intake was similar in the two groups. Compared to census data, the combination of RDD and community controls seems to be more representative of the general population than RDD controls alone. Furthermore, the inclusion of the community group had little impact on the magnitude of risk estimates for most variables, while enhancing statistical power.

CONCLUSIONS

Community-based recruitment was found to be an efficient and feasible method to recruit AA controls.

To be involved or not to be involved: a survey of public preferences for self-involvement in decision-making involving mental capacity (competency) within Europe

BACKGROUND

The Council of Europe has recommended that member states of European Union encourage their citizens to make decisions about their healthcare before they lose capacity to do so. However, it is unclear whether the public wants to make such decisions beforehand.

AIM

To examine public preferences for self-involvement in end-of-life care decision-making and identify associated factors.

DESIGN

A population-based survey with 9344 adults in England, Belgium, Germany, Italy, the Netherlands, Portugal and Spain.

RESULTS

Across countries, 74% preferred self-involvement when capable; 44% preferred self-involvement when incapable through, for example, a living will. Four factors were associated with a preference for self-involvement across capacity and incapacity scenarios, respectively: higher educational attainment ((odds ratio = 1.93-2.77), (odds ratio = 1.33-1.80)); female gender ((odds ratio = 1.27, 95% confidence interval = 1.14-1.41), (odds ratio = 1.30, 95% confidence interval = 1.20-1.42)); younger-middle age ((30-59 years: odds ratio = 1.24-1.40), (50-59 years: odds ratio = 1.23, 95% confidence interval = 1.04-1.46)) and valuing quality over quantity of life or valuing both equally ((odds ratio = 1.49-1.58), (odds ratio = 1.35-1.53)). Those with increased financial hardship (odds ratio = 0.64-0.83) and a preference to die in hospital (not a palliative care unit) (odds ratio = 0.73, 95% confidence interval = 0.60-0.88), a nursing home or residential care (odds ratio = 0.73, 95% confidence interval = 0.54-0.99) were less likely to prefer self-involvement when capable. For the incapacity scenario, single people were more likely to prefer self-involvement (odds ratio = 1.34, 95% confidence interval = 1.18-1.53).

CONCLUSIONS

Self-involvement in decision-making is important to the European public. However, a large proportion of the public prefer to not make decisions about their care in advance of incapacity. Financial hardship, educational attainment, age, and preferences regarding quality and quantity of life require further examination; these factors should be considered in relation to policy.

Risk of childhood acute lymphoblastic leukaemia following parental occupational exposure to extremely low frequency electromagnetic fields

Background:

Earlier studies have reported moderate increases in the risk of acute lymphoblastic leukaemia (ALL) among children whose mothers have been occupationally exposed to extremely low frequency (ELF) electromagnetic fields. Other studies examining parental occupational exposure to ELF and ALL have reported mixed results.

Methods:

In an Australian case–control study of ALL in children aged <15 years, parents were asked about tasks they undertook in each job. Exposure variables were created for any occupational exposure before the birth of the child, in jobs 2 years before birth, in jobs 1 year before birth and up to 1 year after birth.

Results:

In all, 379 case and 854 control mothers and 328 case and 748 control fathers completed an occupational history. Exposure to ELF in all time periods was similar in case and control mothers. There was no difference in exposure between case and control fathers. There was no association between maternal (odds ratio (OR)=0.96; 95% CI=0.74–1.25) or paternal (OR=0.78; 95% CI=0.56–1.09) exposure to ELF any time before the birth and risk of childhood ALL.

Conclusion:

We did not find an increased risk of ALL in offspring of parents with occupational exposure to ELF.

Availability of driver's license master lists for use in government-sponsored public health research

Although the percentage of US drivers with valid driver's licenses varies from state to state, it has historically been high enough to constitute a useful sampling frame for many public health purposes. Over the past decade, states have had to restrict access to this information to comply with the Driver's Privacy Protection Act (18 U.S.C. 2721-2725). In 2009 and 2010, the authors conducted a survey of all 50 states on the availability of master lists of licensed drivers to be used to contact citizens of each state for research purposes. A hypothetical situation requiring driver's license data was sent to each state's responsible government agency for review. In addition, the authors collected data on opt-out mechanisms available to drivers, costs to researchers, and additional state privacy policies pertaining to driver's license files. A total of 42 states (84%) responded; 16 (32%) states allowed access to data, 4 (8%) states were unable to respond to the hypothetical situation, and 22 (44%) states denied access to data. A total of 74,697,574 records were available from the 16 states providing driver's license data. Although the Driver's Privacy Protection Act has restricted access to data on licensed drivers, these data are still an available resource in many states.

Representativeness of child controls recruited by random digit dialling

Recruiting control subjects who are representative of the population from which the cases are drawn is a challenge in case-control studies. This paper examines the performance of random digit dialling (RDD) in obtaining a control sample, and the sample's representativeness of the population with respect to socio-economic status. The study subjects were recruited from 2003 to 2006 for a national, population-based case-control study investigating causes of acute lymphoblastic leukaemia (ALL) in children <15 years of age in Australia. Control families' addresses were linked to Australian Bureau of Statistics Census 2006 Collection Districts and thus to Socio-Economic Indexes for Area scores, which are area-based measures of socio-economic status. These scores were compared with those of all collection districts where families lived. We estimate that 55% of eligible families in the RDD sample agreed to participate in the study. Participation was directly related to socio-economic status with those of highest economic status most likely to participate. Completeness of participation in the components of data collection was similarly related to socio-economic status. This evidence of selection according to socio-economic status indicates that there may also be selection with respect to other factors potentially important in the aetiology of ALL.

Assessment of a commercial searchable population directory as a means of selecting controls for case-control studies

We explored the feasibility of using SalesGenie, a commercially available database, as a potential alternative to traditional methods of selecting controls for population-based case-control studies. An attractive feature of this particular database is that it permits a search within specific age ranges, geographic locations, and household income. Information on 1,068 cases reported to the California Cancer Registry between 2001 and 2005 was entered manually into the SalesGenie Web-based search engine. The frequency of Registry-to-SalesGenie matches was then compared with the frequency of matching the registry data to the California Department of Motor Vehicles (DMV) records. Our findings indicate that the SalesGenie database is currently less comprehensive than DMV records. Nevertheless, Web-based population data sources may provide a potential alternative for population-based studies when used in conjunction with other methods, particularly in states where DMV records are not accessible to researchers.

Family history and risk of renal cell carcinoma: results from a case-control study and systematic meta-analysis

We conducted a case-control analysis, a family-based population analysis, and a meta-analysis to assess the role of family history of cancer and kidney cancer in association with the risk of renal cell carcinoma (RCC). A total of 325 cases and 329 controls were identified from an ongoing case-control study of RCC. Study variables were assessed through 45-minute structured face-to-face interviews. In the case-control analysis, a family history of any cancer (in first-degree relatives) was associated with a nonsignificant 1.2-fold increase in RCC risk [95% confidence interval (95% CI), 0.8-1.6]. The risk increased to 1.7 and became significant when the relative was a sibling (95% CI, 1.1-2.5). A family history of kidney cancer (kidney cancer in first-degree relatives) was associated with a 4.3-fold significantly increased risk of RCC (95% CI, 1.6-11.9). The cases reported a total of 2,536 first-degree relatives of which 21 (0.8%) had kidney cancer, and the controls reported a total of 2,333 first-degree relatives of which 5 (0.2%) had kidney cancer (P=0.003). In the family-based population analysis, a family history of kidney cancer was associated with a 2.8-fold increased risk of RCC (95% CI, 1.0-7.8). The meta-analysis further confirmed this significant association with a 2.2-fold increased risk of RCC (95% CI, 1.6-2.9). To our knowledge, this is the first study to use three analytic strategies to investigate the association between a family history of kidney cancer and risk of RCC, and the first systematic evaluation of the relative risk for developing RCC associated with family history.

Flexible Frames and Control Sampling in Case-Control Studies: Weighters (Survey Statisticians) Versus Anti-Weighters (Epidemiologists)

We propose two innovations in statistical sampling for controls to enable better design of population-based case-control studies. The main innovation leads to novel solutions, without using weights, of the difficult and long-standing problem of selecting a control from persons in a household. Another advance concerns the drawing (at the outset) of the households themselves and involves random-digit dialing with atypical use of list-assisted sampling. A common element throughout is that one capitalizes on flexibility (not broadly available in usual survey settings) in choosing the frame, which specifies the population of persons from which both cases and controls come.

Comparability on knowledge, attitudes, and behaviors between STD clinic clients and high-risk individuals in community

OBJECTIVES

To assess the feasibility and generalizability of STD clinic samples for studying STD-related knowledge, attitudes, and behaviors (KAB), and healthcare preferences among individuals at high risk for STDs in the same community.

STUDY DESIGN

An STD clinic and a community sample were selected from each of two urban areas in New York State. At each STD clinic, 100 individuals were interviewed. In each community, about 400 individuals were selected by random-digit-dialing telephone survey during the same period. Community sample participants were defined as having high-risk profiles on the basis of five items related to their sexual behaviors.

RESULTS

The STD clinic samples were younger and had a larger proportion of men and nonwhite people compared with the high-risk community samples. Although the majority of STD clinic clients would seek healthcare at the STD clinics, high-risk community participants were more likely to prefer private doctors for STDs care (P < .0001 for both areas). Overall STD-related KAB were similar between STD clinic and high-risk community samples; however, STD clinic clients may be more knowledgeable about specific STDs and more likely to feel embarrassment about getting an STD. The findings comparing KAB between high-risk community subjects and STD clinic attendees also varied by geographic location.

CONCLUSIONS

STD clinic samples may not be sufficiently representative of community STD-related KAB collected by telephone surveys, even for that subset of community respondents with high-risk behaviors associated with STDs.

US and France adult fruit and vegetable consumption patterns: an international comparison

BACKGROUND/OBJECTIVES

To observe fruit and vegetable consumption as it relates to body mass index (BMI) and other variables, by analyzing the health surveys of two countries -- the United States and France -- with traditionally distinct diets, and identifying factors that may explain the differences.

SUBJECTS/METHODS

Two nationally representative surveys that assess food intake via 24-h diet recalls. Respondents include 2126 women and 1911 men from the US National Health and Nutrition Examination Survey, and 1572 women and 1141 men from the French Nutrition Barometer Survey. Standard linear regression models and t-tests of both simple and predictive marginal means were run employing the software package SUDAAN.

RESULTS

Americans appear to consume fruits and vegetables less often than their French counterparts (1.04 vs 1.33 times per day fruits; 1.98 vs 2.29 times per day vegetables). American men consume fruits and vegetables least often (0.98 times per day fruits; 1.88 times per day vegetables) than do American women or French men (1.10 vs 1.25 times per day fruits; 2.07 vs 2.18 times per day vegetables). French women consume fruits and vegetables most often (1.41 times per day fruits; 2.41 times per day vegetables). The French have lower mean BMI than Americans (23.34 vs 28.22 women; 25.20 vs 28.02 men). Regression analyses showed that age, BMI and educational attainment are strongly associated with frequency of consumption.

CONCLUSIONS

These results support our hypothesis that the French tend to eat fruits and vegetables more often than Americans. This study proves to be an important first step in determining some of the influential factors that may affect various populations' consumption of fruits and vegetables.

Survey research methods in evaluation and case-control studies

Survey research methods are widely used in two types of analytic studies: evaluation studies that measure the effects of interventions; and population-based case-control studies that investigate the effects of various risk factors on the presence of disease. This paper provides a broad overview of some design and analysis issues related to such studies, illustrated with examples. The lack of random assignment to treatment and control groups in many evaluation studies makes controlling for confounders critically important. Confounder control can be achieved by matching in the design and by various alternative methods in the analysis. One popular analytic method of controlling for confounders is propensity scoring, which bears a close resemblance to survey weighting. The use of population-based controls has become common in case-control studies. For reasons of cost, population-based controls are often identified by telephone surveys using random digit dialling (RDD) sampling methods. However, RDD surveys are now experiencing serious problems with response rates. A recent alternative approach is to select controls from frames such as driver license lists that contain valuable demographic information for use in matching. Methods of analysis developed in the survey sampling literature are applicable, at least to some degree, in the analyses of evaluation and population-based case-control studies. In particular, the effects of complex sample designs can be taken into account using survey sampling variance estimation methods. Several survey analysis software packages are available for carrying out the computations.

Incentives for survey participation when are they "coercive"?

Monetary incentives are increasingly used to help motivate survey participation. This article summarizes several theories underlying the use of incentives and briefly reviews research demonstrating their intended and unintended effects on response rates, sample composition, response bias, and response quality. It also considers the evidence for the effectiveness of incentives in reducing nonresponse bias. Institutional review boards have begun to ask whether, and under what conditions, the use of monetary incentives to induce participation might be coercive and to question the use of such incentives in surveys of "vulnerable" populations, including surveys of injury and violence. The article reviews the ethical principles underlying the requirement for voluntary informed consent as well as current regulations and a broad theoretical and empirical literature bearing on this question, concluding that incentives are never coercive. The question of whether they exert "undue influence" in a specific situation is more difficult, but it may be the wrong question to ask. The article concludes with several recommendations designed to ensure the ethical use of incentives in surveys on violence and injury.

Hershey Medical Center Technical Workshop Report: optimizing the design and interpretation of epidemiologic studies for assessing neurodevelopmental effects from in utero chemical exposure

Neurodevelopmental disabilities affect 3-8% of the 4 million babies born each year in the U.S. alone, with known etiology for less than 25% of those disabilities. Numerous investigations have sought to determine the role of environmental exposures in the etiology of a variety of human neurodevelopmental disorders (e.g., learning disabilities, attention deficit-hyperactivity disorder, intellectual disabilities) that are manifested in childhood, adolescence, and young adulthood. A comprehensive critical examination and discussion of the various methodologies commonly used in investigations is needed. The Hershey Medical Center Technical Workshop: Optimizing the design and interpretation of epidemiologic studies for assessing neurodevelopmental effects from in utero chemical exposure provided such a forum for examining these methodologies. The objective of the Workshop was to develop scientific consensus on the key principles and considerations for optimizing the design and interpretation of epidemiologic studies of in utero exposure to environmental chemicals and subsequent neurodevelopmental effects. (The Panel recognized that the nervous system develops post-natally and that critical periods of exposure can span several developmental life stages.) Discussions from the Workshop Panel generated 17 summary points representing key tenets of work in this field. These points stressed the importance of: a well-defined, biologically plausible hypothesis as the foundation of in utero studies for assessing neurodevelopmental outcomes; understanding of the exposure to the environmental chemical(s) of interest, underlying mechanisms of toxicity, and anticipated outcomes; the use of a prospective, longitudinal cohort design that, when possible, runs for periods of 2-5 years, and possibly even longer, in an effort to assess functions at key developmental epochs; measuring potentially confounding variables at regular, fixed time intervals; including measures of specific cognitive and social-emotional domains along with non-cognitive competence in young children, as well as comprehensive measures of health; consistency of research design protocols across studies (i.e., tests, covariates, and analysis styles) in an effort to improve interstudy comparisons; emphasis on design features that minimize introduction of systematic error at all stages of investigation: participant selection, data collection and analysis, and interpretation of results; these would include (but not be limited to) reducing selection bias, using double-blind designs, and avoiding post hoc formulation of hypotheses; a priori data analysis strategies tied to hypotheses and the overall research design, particularly for methods used to characterize and address confounders in any neurodevelopmental study; actual quantitative measurements of exposure, even if indirect, rather than methods based on subject recall; careful examination of standard test batteries to ensure that the battery is tailored to the age group as well as what is known about the specific neurotoxic effects on the developing nervous system; establishment of a system for neurodevelopmental surveillance for tracking the outcomes from in utero exposure across early developmental time periods to determine whether central nervous system injuries may be lying silent until developmentally challenged; ongoing exploration of computerized measures that are culturally and linguistically sensitive, and span the age range from birth into the adolescent years; routine incorporation of narrative in manuscripts concerning the possibility of spurious (i.e., false positive and false negative) test results in all research reportage (this can be facilitated by detailed, transparent reporting of design, covariates, and analyses so that others can attempt to replicate the study); forthright, disciplined, and intellectually honest treatment of the extent to which results of any study are conclusive--that is, how generalizable the results of the study are in terms of the implications for the individual study participants, the community studied, and human health overall; confinement of reporting to the actual research questions, how they were tested, and what the study found, and avoiding, or at least keeping to a minimum, any opinions or speculation concerning public health implications; education of clinicians and policymakers to critically read scientific reports, and to interpret study findings and conclusions appropriately; and recognition by investigators of their ethical duty to report negative as well as positive findings, and the importance of neither minimizing nor exaggerating these findings.

Characteristics that predict locating and interviewing mothers identified by a state birth defects registry and vital records

BACKGROUND

State vital records are often used to select population-based controls in record-linkage studies of birth defects. However, locating and contacting individuals based on these data sources to collect additional data can be a challenge.

METHODS

A large case-control study of air quality and birth defects was conducted in 7 Texas counties in which cases were selected from the Texas Birth Defects Registry and controls from state vital records. In 2004, data from these sources were used to trace mothers of cases and controls who delivered babies in the year 2000 (n=2477) for participation in a computer-assisted telephone interview. A number of factors that predicted whether an individual would be located and interviewed were identified.

RESULTS

Between March and August 2004, 38% of the mothers were located, and 38% of the located mothers were interviewed. Case mothers were more likely than control mothers to be located (44 vs. 30%) and, if located, to be interviewed (43 vs. 31%). We compared the characteristics of mothers who were not located (case n=760; control n=777), mothers who were located but not interviewed (case n=344; control n=236), and mothers who were interviewed (case n=256; control n=104). Among both cases and controls, older mothers (>or=30 years) were more likely than younger mothers to be located, and non-Hispanic black mothers were least likely to be located and interviewed.

CONCLUSIONS

Despite the utility of vital records as a source of population-based controls in record-linkage analyses, the poor response rate discourages the use of these data sources to contact individuals for a follow-up study 4 years after delivery.

Socioeconomic status and childhood leukaemia: a review

BACKGROUND

A long-held view links higher socioeconomic status (SES) to higher rates of childhood leukaemia. Some recent studies exhibit associations in the opposite direction.

METHODS

We reviewed journal literature through August 2002 for associations between childhood leukaemia and socioeconomic measures. We determined the direction of each association and its P-value. We described the results with regard to study design, calendar period, geographic locale, and level of the socioeconomic measures (individual or ecological). For measures with sufficient number of results, we computed summary P-values across studies.

RESULTS

Case-control studies conducted in North America since 1980 have involved subject interviews or self-administered questionnaires and have consistently reported inverse (negative) associations of childhood leukaemia with individual-level measures of family income, mother's education, and father's education. In contrast, associations have been consistently positive with father's occupational class in record-based case-control studies and with average occupational class in ecological studies.

CONCLUSIONS

Connections of SES measures to childhood leukaemia are likely to vary with place and time. Validation studies are needed to estimate SES-related selection and participation in case-control studies. Because different socioeconomic measures (such as income and education) and individual-level and ecological-level measures may represent different risk factors, we advise researchers to report these measures separately rather than in summary indices of social class.

Adult tetanus, diphtheria and pertussis immunization: knowledge, beliefs, behavior and anticipated uptake

BACKGROUND

Lifetime protection against pertussis has been adopted as a goal of immunization programs in Canada. To anticipate adult coverage with a combined product containing tetanus (T) and diphtheria (d) toxoids and acellular pertussis (aP) vaccine as a booster dose, we conducted a survey of households in British Columbia, Canada.

METHODS

In a random telephone survey involving 800 adults, 25 years of age and older, we assessed current behaviors related to adult Td immunization and beliefs regarding pertussis vaccine under various scenarios relevant to adult decision-making.

RESULTS

Forty-five percent of participants reported having received tetanus vaccine within the previous 10 years; this rate was lowest amongst elderly persons 65 years of age or more (28%). On multi-variate analysis, being up-to-date with tetanus immunization was independently associated with belief that an adult should be immunized against tetanus and perception that tetanus is life-threatening and inversely associated with being elderly. At baseline, 59% of respondents indicated willingness to receive pertussis immunization if provided free; this increased to 76% following sequential information about communicability and severity of pertussis illness and safety, efficacy and convenience of vaccine and up to 87% if accompanied by physician or nurse recommendation. Sixty-three percent of adults indicated they would receive the vaccine if required to pay $40.00 (Cdn) for it.

CONCLUSIONS

Personal risk perception, public funding and physician recommendation are important to adults when considering tetanus and pertussis immunization. These factors may be relevant as immunization programs are expanded to include more adults generally.

The Transtheoretical Model of Behavior Change and Smokers in Southern Appalachia

BACKGROUND

The southern Appalachian states show a high prevalence of smoking, with associated high rates of both heart disease and cancer, yet cultural differences raise questions concerning the applicability of the most frequently used model for smoking cessation, the transtheoretical model, for smokers from this region of the country.

OBJECTIVE

To identify, by examining the applicability of the transtheoretical model for southern Appalachian smokers, the percentage of individuals in each of the five stages of change, the use of the processes of change from the trans-theoretical model, and the scores on recognized predictors of smoking cessation including the temptation to smoke, the perceived barriers to cessation, the pros and cons of smoking, and nicotine dependence.

METHODS

This population-based, descriptive, cross-sectional study used a random sample of 3,800 telephone numbers, which were called up to eight times. The 659 smokers or former smokers who agreed to participate were mailed a written questionnaire consisting of six well-established scales that measure constructs from the transtheoretical model. The final sample consisted of 357 usable questionnaires.

RESULTS

The distribution of smokers in northeastern Tennessee differed from national samples across the first three stages of change, with 56% in precontemplation, as compared with previous findings of 40% in national samples. The subjects' scores for the pros of smoking were similar across the stages of change in this sample, and although the scores for the cons differed significantly across the stages in the sample, post hoc analysis indicated that the only significant change occurred between precontemplation and contemplation. The scores for temptation to smoke did not differ significantly across the stages of change in this sample.

DISCUSSION

Smokers from Appalachian Tennessee differ from smokers in other parts of the United States, and these findings raise questions about the applicability of the transtheoretical model for this population.

Participants and refusers in a telephone interview about hormone replacement therapy were equally likely to be taking it

OBJECTIVE

To address a major concern in pharmacoepidemiology studies related to whether the characteristics of responders are different from those who refuse to participate.

STUDY DESIGN AND SETTING

We compared utilization of postmenopausal hormone replacement therapy (HRT) in women who agreed to participate in a telephone interview on HRT utilization and in women who refused to participate in the telephone interview. Information on HRT utilization among responders and refusers was independently available to us from a claims database (the Healthcare Management Alternatives, HMA, in Philadelphia), showing drugs dispensed to these patients.

RESULTS

Out of a random sample of 213 women selected from the claims database whom we contacted, 154 (72.3%) women agreed to participate and 59 (32.7%) women refused. Among the 154 women who agreed to participate, 79 (51.3%, 95% CI: 43.1-59.4%) were shown by the database to have been dispensed an HRT during the 15-month period January 1995 through March 1996. Among the 59 women who refused to participate, 30 (50.8%, 95% CI: 37.5-64.1%) were shown by the database to have been dispensed an HRT during the same period.

CONCLUSION

Thus, we have evidence that use of HRT was almost identical in responders and nonresponders.

Internet use and epidemiologic investigation of gastroenteritis outbreak

In March 2000, a large outbreak of gastroenteritis occurred in a community where a regional computer network provides free Internet access for 42% of the households. We conducted an epidemiologic investigation using the Internet for data collection. Norovirus was identified in stool samples of nine patients but not in the municipal water supply. Of households with access to the network, 19% participated in the survey. The overall attack rate by household was 63%. Drinking water from the nonchlorinated community water system was associated with illness (relative risk [RR] 1.6; 95% confidence interval [CI] 1.1 to 2.2); drinking water only from a private well was associated with decreased likelihood of illness (RR 0.3; 95% CI 0.1 to 0.8). Data collection through the Internet was efficient. Internet surveys may become more common in epidemiologic investigations and have the potential to provide data rapidly, enabling appropriate public health action. However, methods should be developed to increase response rates and minimize bias.

Psoriasis Is Common, Carries a Substantial Burden Even When Not Extensive, and Is Associated with Widespread Treatment Dissatisfaction

The impact of psoriasis on quality of life has been studied in select patient populations. Population-based data detailing the distribution of extent of disease, associated problems in everyday life, and treatment satisfaction for the US population have been lacking. Our population-based survey indicates that approximately 4.5 million adults have been diagnosed as having psoriasis. Most (59%) have little or no involvement, but 650,000 adults have at least three palms of body surface involved and more than 1,000,000 indicate substantial dissatisfaction with their treatment. Only 5% of patients (56,000) who report severe dissatisfaction with current therapy have extensive disease (10 palms). Many individuals with little psoriasis at the time of interview considered the disease to be a large problem in everyday life.

African Americans' attitudes toward cigarette excise taxes

OBJECTIVES

This study examined African Americans' opinions regarding cigarette excise taxes and other tobacco control issues.

METHODS

A stratified cluster sample of US congressional districts represented by African Americans was selected. African Americans from 10 districts were interviewed.

RESULTS

Forty-seven percent of respondents stated that taxes on tobacco products should be increased, whereas about 30% believed that they should be reduced. Almost 75% disagreed that raising taxes on tobacco products is unfair to African Americans, and 57.9% reported that they would not be opposed to increasing taxes on cigarettes even if low-income smokers would be hit the hardest.

CONCLUSIONS

The present results indicate substantial support for cigarette excise taxes among African Americans.

The NICHD Women's Contraceptive and Reproductive Experiences Study: methods and operational results

PURPOSE

This paper presents methods and operational results of a population-based case-control study examining the effects of oral contraceptive use on breast cancer risk among white and black women aged 35-64 years in five U.S. locations.

METHODS

Cases were women newly diagnosed with breast cancer during July 1994 through April 1998. Controls were identified through random digit dialing (RDD) using unclustered sampling with automated elimination of nonworking numbers. Sampling was density-based, with oversampling of black women. In-person interviews were conducted from August 1994 through December 1998. Blood samples were obtained from subsets of cases and controls, and tissue samples were obtained from subsets of cases. A computerized system tracked subjects through study activities. Special attention was devoted to minimizing exposure misclassification, because any exposure-disease associations were expected to be small.

RESULTS

An estimated 82% of households were screened successfully through RDD. Interviews were completed for 4575 cases (2953 whites; 1622 blacks) and 4682 controls (3021 whites; 1661 blacks). Interview response rates for cases and controls were 76.5% and 78.6%, respectively, with lower rates for black women and older women.

CONCLUSIONS

The methodologic details of this large collaboration may assist researchers conducting similar investigations.

Commentary: Trade-offs in the development of a sample design for case-control studies

The recent article, "Comparison of Telephone Sampling and Area Sampling: Response Rates and Within-Household Coverage" (Am J Epidemiol 2001;153:1119-27), raised a number of issues related to two sampling methodologies that can be used for selecting population-based controls for case-control studies: random digit dialing (RDD) and area probability sampling. Some of these issues are discussed in this commentary in more detail to help in making sample design decisions, including the need to take the analysis plan into account when developing a sample design. Data from the paper are used to illustrate how the choice of sample design can affect analyses. Relative costs associated with the two methodologies as well as variance and bias concerns are also discussed in detail. Sample coverage issues, including those associated with list-assisted RDD, are considered, as are some advantages of the list-assisted approach. A discussion of the use of concurrent screening and sampling with an RDD approach as an alternative to periodically selecting fixed sample sizes is provided.