Sample representativeness and influence of attrition on longitudinal data collected as part of a national medical career tracking project

BACKGROUND

The Medical Schools Outcomes Database and Longitudinal Tracking Project (MSOD) in New Zealand is one example of a national survey-based resource of medical student experiences and career outcomes. Longitudinal studies of medical students are valuable for evaluating the outcomes of medical programs against workforce objectives. As a prospective longitudinal multiple-cohort study, survey response rates at each collection point of MSOD vary. This paper assesses the effects of participant non-response rates on MSOD data.

METHODS

Demographic variables of MSOD respondents between 2012 and 2018 were compared to the distribution of the demographic variables in the population of all NZ medical graduates to ascertain whether respondent samples at multiple survey collection points were representative of the population. Analysis using logistic regression assessed the impact of participant non-response on variables at collection points throughout MSOD.

RESULTS

2874 out of a total population of 2939 domestic medical students graduating between 2012 and 2018 responded to MSOD surveys. Entry and exit surveys achieved response rates around 80% and were broadly representative of the total population on demographic variables. Post-graduation survey response rates were around 50% of the total population of graduates and underrepresented graduates from the University of Auckland. Between the entry and exit and the exit and postgraduation year three samples, there was a significant impact of non-response on ascribed variables, including age at graduation, university, gender and ethnic identity. Between the exit and postgraduation year one sample, non-response significantly impacted ascribed and non-ascribed variables, including future practice intentions.

CONCLUSION

Samples collected from MSOD at entry and exit are representative, and findings from cross-sectional studies using these datasets are likely generalisable to the wider population of NZ medical graduates. Samples collected one and three years post-graduation are less representative. Researchers should be aware of this bias when utilizing these data. When using MSOD data in a longitudinal manner, e.g. comparing the change in career intentions from one collection point to the next, researchers should appropriately control for bias due to non-response between collection points. This study highlights the value of longitudinal career-tracking studies for answering questions relevant to medical education and workforce development.

Women's interest in surgery as a career in the early postgraduate period: a national longitudinal study

BACKGROUND

Women remain underrepresented in Surgery in Aotearoa New Zealand (AoNZ). This study described interest in surgical careers by gender in the early postgraduate period and associated influencing factors.

METHODS

AoNZ medical graduates between 2012 and 2016 responding to an Exit Questionnaire (EQ) at graduation and 3 years later (PGY3) as part of the Medical Schools Outcomes Database and Longitudinal Tracking Project (MSOD) were included. Analyses of specialty preferences and influences by gender were performed.

RESULTS

Of 992 participants, 58% were women. At EQ, 158 participants (16%) had a surgical preference: 21% of men and 14% of women (P < 0.01). By PGY3, this was 20% of men and 10% of women (P < 0.01). A logistic regression found women were half as likely as men to have a surgical preference at PGY3. Those with a surgical preference at EQ were over 23 times more likely to have a surgical preference at PGY3, irrespective of gender. There were significant differences in self-reported career influencing factors between women and men at EQ and PGY3, as well as between PGY3 women with a surgical and those with a non-surgical preference. These included nature of the specialty, training requirements, lifestyle, family and personal factors.

CONCLUSIONS

Increasing the proportion of women in Surgery requires a multifaceted approach starting during medical school and continuing through early postgraduate years. More needs to be done to make surgical experiences as an undergraduate and junior doctor appealing to women.

Effects of a regional-rural immersion program in Northland, New Zealand, on returning to work in that region

INTRODUCTION

It is well established that rural workforce outcomes are more likely among medical graduates who spend time training in non-urban areas; however, fewer studies have assessed whether graduates are more likely to return to the specific area where they undertook rural training.

OBJECTIVE

This study aimed to determine whether graduates who had undertaken a regional-rural immersion program in Northland, NZ, were more likely to have returned to work in Northland as of mid-2021, relative to peers who did not participate.

DESIGN

This prospective cohort study used longitudinal tracking survey responses, medical school administrative data and workforce outcome information. A multinomial model, accounting for other covariates, was built to determine the association between graduates practising in Northland (population ⟨ 100 000), which encompasses both rural (population ⟨ 25 000) and regional (25 000 ⟩ population ⟨ 100 000) areas, and having participated in a Northland-based immersion program during medical school. The study population was University of Auckland domestic medical students graduating between 2009 and 2018, inclusive. Immersion program participants who responded to longitudinal career tracking surveys were included in the study sample.

FINDINGS

The final sample size was 1320 students (80% of population of interest). Graduates who undertook the Northland immersion program (n = 169) were more likely than non-participants (n = 1151) to be working in Northland as of 2020-2021 (relative risk: 3.2).

DISCUSSION AND CONCLUSION

Regional-rural immersion programs might preferentially build workforces in that specific region; however, further research is required to understand whether these findings are generalizable, and the main reasons for this effect.

How rural is rural? The relationship between rural background of medical students and their career location intentions

OBJECTIVE

Rural background is associated with greater interest in rural practice. However, there is no universally agreed definition of 'rural' background used in medical school selection. This study explored the association between definitions of 'rural' background and students' intended career locations.

DESIGN

Prospective cohort study using survey data on career intention, hometown size, rurality of background, home address, high school and intended career location.

SETTING

University of Auckland, New Zealand (NZ).

PARTICIPANTS

Commencing medical students 2009-2017, inclusive.

MAIN OUTCOME MEASURES

Univariate associations between student background according to 7 definitions of 'rural', and 3 definitions of intended practice location based on population size: urban intention (>100 000); regional intention (25 000-100 000); rural intention (<25 000).

RESULTS

The sample size was 1592 students. 27.4% had a rural background by at least one definition. All definitions of rural background were associated with a greater rural intention. Applying a restrictive definition of rural (population<25 000) was associated with a higher likelihood of rural intention, but captured a smaller number of students. There was strong agreement between the population size of a student's background and intended practice location (chi-square P < .0001).

CONCLUSION

Rural intention varies by definition, but the number of students captured by each definition is important. Applying a binary or overly restrictive definition may limit interested students. Medical schools should adopt a definition of 'rural' that optimises the number of eligible students and their propensity to work rurally. Further, alternative ways of identifying students with rural intentions without a rural background should be explored.

National study of the impact of rural immersion programs on intended location of medical practice in New Zealand

INTRODUCTION

New Zealand (NZ) faces an ongoing shortage of rural medical professionals. In an effort to increase interest in rural practice, both of the medical schools in NZ offer rural immersion programs as well as rural entry pathways. The aim of this study was to compare the effect of long (>33-week) rural immersion with a short (5-week interprofessional) rural immersion or no rural immersion on the career location intentions of NZ medical students.

METHODS

This observational study used linked data from the Commencing Medical Students Questionnaire (CMSQ) and Exit Questionnaire (EQ), collected between 2011 and 2017 as part of the Medical Schools Outcomes Database project, along with information on whether or not a student undertook a rural immersion program. The main outcome measure was EQ career location intention (Rural (population 100 000)). The explanatory variables were rural immersion (long, short, none), age, ethnicity, background, CMSQ career location intention, gender, specialisation preferences and interest in rural medicine. In addition to univariate analysis, data were used to build a multinomial model to determine relative associations of these variables with the outcome.

RESULTS

Full data were available for 1367 NZ medical students (47% of all students during the time period). Of these, 17.4% had undertaken a long or short rural immersion program. In univariate analysis, age was the only variable that did not significantly predict EQ rural intention outcome. In the multivariate model, rural immersion was a significant independent predictor of EQ career location intention. Students taking a long rural immersion were 6.4 and 4.4 times more likely to select a Rural or Regional intention, respectively, than those with no rural immersion. This strong effect on rural intentions was seen regardless of background. CMSQ career location intention, background, ethnicity, rural club membership and preference for general practice were also significant predictors. While short rural immersion did not have an independent effect, this finding should be interpreted with caution given the smaller number of students and the response rate.

CONCLUSIONS

Long rural immersion is highly beneficial for increasing interest in rural work, increasing the likelihood that medical students will intend to work outside an urban setting. Students who signal an early rural intention are strong candidates for such programs later in their course, regardless of their background. A three-category classification for geographic background and career location intention permitted a more detailed understanding of the interplay among demographic variables and rural immersion in influencing career intentions. Following cohorts into their postgraduate years is needed to ascertain if these career location intentions persist.

Effects of Dopamine and Norepinephrine on Exercise-induced Oculomotor Fatigue

INTRODUCTION

Fatigue-induced impairments in the control of eye movements are detectable via reduced eye movement velocity after a bout of prolonged, strenuous exercise. Slower eye movements caused by neural fatigue within the oculomotor system can be prevented by caffeine, and the upregulation of central catecholamines may be responsible for this effect. This study explored the individual contribution of dopamine and norepinephrine to fatigue-related impairments in oculomotor control.

METHODS

The influence of a dopamine reuptake inhibitor (methylphenidate) and a norepinephrine reuptake inhibitor (reboxetine) was assessed in 12 cyclists performing 180 min of stationary cycling within a placebo-controlled crossover design. Eye movement kinematics (saccades, smooth pursuit, and optokinetic nystagmus) were measured using infrared oculography. Visual attention was assessed with overt and covert spatial attention tasks.

RESULTS

Exercise-induced fatigue was associated with a 6% ± 8% reduction in the peak velocity of visually guided, reflexive prosaccades. Importantly, both dopamine reuptake inhibition and norepinephrine reuptake inhibition prevented fatigue-related decrements in the peak velocity of prosaccades. Pursuit eye movements, optokinetic nystagmus, and visual attention tasks were unaffected by exercise or drug treatments.

CONCLUSION

Overall, our findings suggest that alterations in norepinephrinergic and dopaminergic neurotransmission are linked with the development of fatigue within circuits that control eye movements. Psychiatric medications that target central catecholamines can exert a protective effect on eye movements after prolonged exercise.

Effects of regular aerobic exercise on visual perceptual learning

This study investigated the influence of five days of moderate intensity aerobic exercise on the acquisition and consolidation of visual perceptual learning using a motion direction discrimination (MDD) task. The timing of exercise relative to learning was manipulated by administering exercise either before or after perceptual training. Within a matched-subjects design, twenty-seven healthy participants (n = 9 per group) completed five consecutive days of perceptual training on a MDD task under one of three interventions: no exercise, exercise before the MDD task, or exercise after the MDD task. MDD task accuracy improved in all groups over the five-day period, but there was a trend for impaired learning when exercise was performed before visual perceptual training. MDD task accuracy (mean ± SD) increased in exercise before by 4.5 ± 6.5%; exercise after by 11.8 ± 6.4%; and no exercise by 11.3 ± 7.2%. All intervention groups displayed similar MDD threshold reductions for the trained and untrained motion axes after training. These findings suggest that moderate daily exercise does not enhance the rate of visual perceptual learning for an MDD task or the transfer of learning to an untrained motion axis. Furthermore, exercise performed immediately prior to a visual perceptual learning task may impair learning. Further research with larger groups is required in order to better understand these effects.

Exercise-Induced Fatigue and Caffeine Supplementation Affect Psychomotor Performance but Not Covert Visuo-Spatial Attention

Fatigue resulting from strenuous exercise can impair cognition and oculomotor control. These impairments can be prevented by administering psychostimulants such as caffeine. This study used two experiments to explore the influence of caffeine administered at rest and during fatiguing physical exercise on spatial attention—a cognitive function that is crucial for task-based visually guided behavior. In independent placebo-controlled studies, cohorts of 12 healthy participants consumed caffeine and rested or completed 180 min of stationary cycling. Covert attentional orienting was measured in both experiments using a spatial cueing paradigm. We observed no alterations in attentional facilitation toward spatial cues suggesting that covert attentional orienting is not influenced by exercise fatigue or caffeine supplementation. Response times were increased (impaired) after exercise and this deterioration was prevented by caffeine supplementation. In the resting experiment, response times across all conditions and cues were decreased (improved) with caffeine. Covert spatial attention was not influenced by caffeine. Together, the results of these experiments suggest that covert attentional orienting is robust to the effects of fatiguing exercise and not influenced by caffeine. However, exercise fatigue impairs response times, which can be prevented by caffeine, suggesting that pre-motor planning and execution of the motor responses required for performance of the cueing task are sensitive to central nervous system fatigue. Caffeine improves response time in both fatigued and fresh conditions, most likely through action on networks controlling motor function.

Fatigue related impairments in oculomotor control are prevented by caffeine

Strenuous exercise can result in an inability of the central nervous system to drive skeletal muscle effectively, a phenomenon known as central fatigue. The impact of central fatigue on the oculomotor system is currently unexplored. Fatigue that originates in the central nervous system may be related to perturbations in the synthesis and metabolism of several neurotransmitters. In this study we examine central fatigue in the oculomotor system after prolonged exercise. The involvement of central neurotransmission was explored by administering caffeine during exercise. Within a double-blind, randomized, repeated measures, crossover design, 11 cyclists consumed a placebo or caffeine solution during 180 min of stationary cycling. Saccadic eye movements were measured using infra-red oculography. Exercise decreased saccade velocity by 8% (placebo trial). This effect was reversed by caffeine, whereby velocity was increased by 11% after exercise. A non-oculomotor perceptual task (global motion processing) was unaffected by exercise. The human oculomotor system is impaired by strenuous exercise of the locomotor system. Caffeine exerts a protective effect on oculomotor control, which could be related to up-regulated central neurotransmission. In addition, cortical processes supporting global motion perception appear to be robust to fatigue.