Does involvement in a cohort study improve health and affect health inequalities? A natural experiment

Changes in prevalence and patterns of consanguinity in Bradford, UK - evidence from two cohort studies

Background

Research undertaken using the Born in Bradford cohort study identified consanguinity as a major risk factor for congenital anomalies and also reported longer term adverse health outcomes associated with consanguinity.

Methods

We report the prevalence of consanguinity from two cohort studies in the same geographical area with a nine year gap: Born in Bradford (BiB) and Born in Bradford's Better Start (BiBBS). We examine and compare rates of consanguinity and the characteristics of the consanguineous in each study population to examine if and how these have changed in the years between the recruitment periods of 2007-2010 (BiB) and 2016-2019 (BiBBS).

Results

There had been a substantial decrease in consanguineous unions in women of Pakistani heritage, the proportion of women who were first cousins with the father of their baby fell from 39.3% to 27.0%, and those who were other blood relations fell from 23.1% to 19.3%. Only 37.6% of Pakistani heritage women were unrelated to the father of their baby in BiB, but 53.7% were unrelated in BiBBS. All but one White British respondent was unrelated to their baby's father in both cohorts, and around 90% of the 'Other ethnicities' group (i.e., not White British or Pakistani heritage) were unrelated to the baby's father in both cohorts. The reduction was most marked in women of Pakistani heritage who were born in the UK, in those educated to A level or higher and in women under age 25.

Conclusions

An appreciation of changing rates of consanguinity and linked health needs will be valuable to those who commission and provide antenatal, paediatric and genetic services in Bradford and in other areas where consanguinity is likely to be a major risk factor. Falling rates in this city may reflect wider changes in partner choices in similar populations.

Defining and evaluating the Hawthorne effect in primary care, a systematic review and meta-analysis

In 2015, we conducted a randomized controlled trial (RCT) in primary care to evaluate if posters and pamphlets dispensed in general practice waiting rooms enhanced vaccination uptake for seasonal influenza. Unexpectedly, vaccination uptake rose in both arms of the RCT whereas public health data indicated a decrease. We wondered if the design of the trial had led to a Hawthorne effect (HE). Searching the literature, we noticed that the definition of the HE was unclear if stated. Our objectives were to refine a definition of the HE for primary care, to evaluate its size, and to draw consequences for primary care research. We designed a Preferred Reporting Items for Systematic reviews and Meta-Analyses review and meta-analysis between January 2012 and March 2022. We included original reports defining the HE and reports measuring it without setting limitations. Definitions of the HE were collected and summarized. Main published outcomes were extracted and measures were analyzed to evaluate odds ratios (ORs) in primary care. The search led to 180 records, reduced on review to 74 for definition and 15 for quantification. Our definition of HE is "an aware or unconscious complex behavior change in a study environment, related to the complex interaction of four biases affecting the study subjects and investigators: selection bias, commitment and congruence bias, conformity and social desirability bias and observation and measurement bias." Its size varies in time and depends on the education and professional position of the investigators and subjects, the study environment, and the outcome. There are overlap areas between the HE, placebo effect, and regression to the mean. In binary outcomes, the overall OR of the HE computed in primary care was 1.41 (95% CI: [1.13; 1.75]; I 2 = 97%), but the significance of the HE disappears in well-designed studies. We conclude that the HE results from a complex system of interacting phenomena and appears to some degree in all experimental research, but its size can considerably be reduced by refining study designs.

Geographic clusters of objectively measured physical activity and the characteristics of their built environment in a Swiss urban area

Introduction

Evidence suggests that the built environment can influence the intensity of physical activity. However, despite the importance of the geographic context, most of the studies do not consider the spatial framework of this association. We aimed to assess individual spatial dependence of objectively measured moderate and vigorous physical activity (MVPA) and describe the characteristics of the built environment among spatial clusters of MVPA.

Methods

Cross-sectional data from the second follow-up (2014–2017) of CoLaus|PsyCoLaus, a longitudinal population-based study of the Lausanne area (Switzerland), was used to objectively measure MVPA using accelerometers. Local Moran’s I was used to assess the spatial dependence of MVPA and detect geographic clusters of low and high MVPA. Additionally, the characteristics of the built environment observed in the clusters based on raw MVPA and MVPA adjusted for socioeconomic and demographic factors were compared.

Results

Data from 1,889 participants (median age 63, 55% women) were used. The geographic distribution of MVPA and the characteristics of the built environment among clusters were similar for raw and adjusted MVPA. In the adjusted model, we found a low concentration of individuals within spatial clusters of high MVPA (median: 38.5mins; 3% of the studied population) and low MVPA (median: 10.9 mins; 2% of the studied population). Yet, clear differences were found in both models between clusters regarding the built environment; high MVPA clusters were located in areas where specific compositions of the built environment favor physical activity.

Conclusions

Our results suggest the built environment may influence local spatial patterns of MVPA independently of socioeconomic and demographic factors. Interventions in the built environment should be considered to promote physically active behaviors in urban areas.

Do sociodemographic variables and cardiometabolic risk factors moderate the mere-measurement effect on physical activity and sedentary time?

Background

Participation in an assessment may change health behavior. This “mere-measurement effect” may be used for prevention purposes. However, little is known about whether individuals’ characteristics moderate the effect. The objective was to explore whether changes of physical activity (PA) and sedentary time (ST) after a cardiovascular assessment depend on sociodemographic variables and cardiometabolic risk factors.

Methods

A sample of n = 175 adults aged 40 to 65 received baseline assessment including self-administered PA and ST questionnaires and standardized measurement of blood pressure, waist circumference, and blood parameters. After 5 weeks, participants again reported PA and ST without any prior treatment or intervention. Linear regression models were used to analyze the dependence of five-week changes in PA and ST on baseline sociodemographic and cardiometabolic variables.

Results

Men increased transport-related PA more than women (b = 9.3 MET-hours/week, P = .031). Men with higher triglycerides increased transport-related PA less than men with lower triglycerides (b = − 5.6 MET-hours/week, P = .043). Men with higher systolic blood pressure reduced ST more than those with lower systolic blood pressure (b = − 35.7 min/week, P = .028). However, this linear association ceased to exist at a level of approximately 145 mmHg (b of squared association = 1.0, P = .080). A similar relationship was found for glycated hemoglobin and ST.

Conclusions

The findings suggest that sex and cardiometabolic risk factors moderate mere-measurement effects on PA and ST. Researchers and practitioners using mere measurement for prevention purposes may address PA and ST according to these individual characteristics.

Trial registration

ClinicalTrials.govNCT02990039. Registered 7 December 2016. Retrospectively registered.

Konditionierungseffekte in Panel-Untersuchungen

Zusammenfassung. Paneldaten sind für die Untersuchung kausaler Zusammenhänge und die Beantwortung längsschnittlicher Fragestellungen unverzichtbar. Es ist allerdings umstritten, welchen Effekt die wiederholte Befragung von Panelteilnehmern auf die Qualität von Paneldaten hat. Der zu erwartende Lerneffekt der Teilnehmer bei wiederholter Teilnahme wird als Panelkonditionierung bezeichnet und kann sowohl positive als auch negative Folgen für die Validität der Paneldaten aufweisen. Insbesondere bei sensitiven Items werden Auswirkungen auf die soziale Erwünschtheit der gemachten Angaben erwartet. Die verfügbare Evidenz zu Konditionierungseffekten bei sensitiven Fragen legt unterschiedliche Effekte je nach Art der Frage nahe und wurde bisher lediglich in Form narrativer Reviews aufgearbeitet. In der vorliegenden Meta-Analyse werden anhand der verfügbaren experimentellen Evidenz (154 Effektstärken aus 19 Berichten) Konditionierungseffekte in Abhängigkeit von der Art der Frage, sowie der Häufigkeit und der Abstände zwischen den Erhebungen (Dosiseffekte) untersucht. Standardisierte Mittelwertunterschiede zwischen wiederholt teilnehmenden und erstmalig teilnehmenden Probanden werden mittels Mehrebenen-Meta-Regressionen analysiert. Dabei zeigen sich nur geringe Effekte vorheriger Befragungen auf das Antwortverhalten in Folgewellen. Nach aktuellem Stand kann daher davon ausgegangen werden, dass die Qualität von Paneldaten nicht in relevantem Maße von Konditionierungseffekten beeinflusst wird. Grenzen der vorliegenden Meta-Analyse und relevante Forschungslücken werden diskutiert. Eine englische Übersetzung als Rohfassung dieses Artikels finden Sie als Elektronisches Supplement 1. ESM1 .

Considering the Control Group: The Influence of Follow-Up Assessments on Asthma Symptoms

OBJECTIVE

It is unclear whether research participation effects contribute to an improvement in asthma symptoms during clinical trials in the absence of any active intervention. We examined the impact of additional follow-up surveys on caregiver-reported symptoms among control subjects in a series of randomized controlled asthma trials.

METHODS

We analyzed baseline and follow-up data for children (3-10 years) with poorly controlled persistent asthma that participated as control subjects in 1 of 3 randomized trials of urban school-based asthma care (study duration: 7-10 months). We compared mean symptom-free days (SFD) per 2 weeks between baseline and final follow-up; performed bivariate regressions to explore associations between demographics and changes in SFD; and performed multivariate random-effects generalized least square regression to examine the relationship between number of follow-ups beyond baseline (range: 1-10) and changes in SFD over time.

RESULTS

Five hundred and sixteen children were enrolled as controls across the 3 trials (mean age 7.5 years, 61% Black, 28% Hispanic, 81% Medicaid). Mean SFDs increased significantly from baseline to final follow-up (7.8-11.4 days, P < .001). In adjusted analyses, significant improvements in SFD were observed with all follow-up contacts in comparison with baseline. Symptom improvement showed a dose-response relationship with the number of follow-up assessments completed (1, 2-3, 4-5, and 6-10 assessments).

CONCLUSIONS

Children with uncontrolled asthma who participate as controls in clinical trials experience a significant increase in SFD with additional follow-up assessments. This improvement should be considered when designing/analyzing asthma interventions, and may help guide clinical outreach efforts for underserved children with persistent asthma.

Risk factors control for primary prevention of cardiovascular disease in men: Evidence from the Aragon Workers Health Study (AWHS)

Benefits of cardiovascular disease (CVD) risk factors control are well known, but goals achievement remains low. The objective of this study is to evaluate the prevalence of CVD risk factors among men ina worker's cohort with no previous CVD, to study control variations across time and the factors associated with poor control. To this end, we conducted a cohort reexamination (2010-2014) within the context of the Aragon Workers Health Study (AWHS). Data from working characteristics, analytical values and pharmacological prescription were included in the analysis. Prevalences of risk factor diagnosis and control were calculated, as well as factors associated with poor control. The prevalence of CVD risk factors was high. In 2014dyslipidaemia was the most prevalent (85.2%) followed by Hypertension (HT) (42.0%). People under treatment increased for the period analysed (p<0.001). The proportion of people treated varied from 72.2% in Diabetes Mellitus to 31.1% in dyslipidaemia in 2014. 46.2% of the workers with HT were controlled, decreasing to 21.9% in Diabetes and 11.0% in dyslipidaemia (2014). Working in a turn different to central shift was associated with poor control, especially for those working at night with HT (Odds Ratio in 2010: 3.6; Confidence Interval 95% 1.8-7.4) and dyslipidaemia (Odds Ratio 2010: 4.7; Confidence Interval 95% 1.3-16.4). We conclude that, although CVD control has increased significantly for the period studied, there are still many people that do not receive any treatment, and control goals are normally not achieved.