Local NO2 concentrations and asthma among over-50s in Ireland: A microdata analysis

BACKGROUND

Links between air pollution and asthma are less well established for older adults than some younger groups. Nitrogen dioxide (NO2) concentrations are widely used as an indicator of transport-related air pollution, and some literature suggests NO2 may directly affect asthma.

METHODS

This study used data on 8162 adults >50 years old in the Republic of Ireland to model associations between estimated annual outdoor concentration of NO2 and the probability of having asthma. Individual-level geo-coded survey data from The Irish Longitudinal Study on Ageing (TILDA) were linked to model-based estimates of annual average NO2 at 50 m resolution. Asthma was identified using two methods: self-reported diagnoses and respondents' use of medications related to obstructive airway diseases. Logistic regressions were used to model the relationships.

RESULTS

NO2 concentrations were positively associated with the probability of asthma [marginal effect (ME) per 1 ppb of airborne NO2 = 0.24 percentage points asthma self-report, 95% confidence interval (CI) 0.06-0.42, mean asthma prevalence 0.09; for use of relevant medications ME = 0.21 percentage points, 95% CI 0.049-0.37, mean prevalence 0.069]. Results were robust to varying model specification and time period. Respondents in the top fifth percentile of NO2 exposure had a larger effect size but also greater standard error (ME = 2.4 percentage points asthma self-report, 95% CI -0. 49 to 5.3).

CONCLUSIONS

Associations between local air pollution and asthma among older adults were found at relatively low concentrations. To illustrate this, the marginal effect of an increase in annual average NO2 concentration from sample minimum to median (2.5 ppb) represented about 7-8% of the sample average prevalence of asthma.

Characterising urban green space density and footpath-accessibility in models of BMI

Background

While exposure to urban green spaces has been associated with various physical health benefits, the evidence linking these spaces to lower BMI, particularly among older people, is mixed. We ask whether footpath availability, generally unobserved in the existing literature, may mediate exposure to urban green space and help explain this volatility in results. The aim of this study is to add to the literature on the association between urban green space and BMI by considering alternative measures of urban green space that incorporate measures of footpath availability.

Methods

We conduct a cross-sectional study combining data from The Irish Longitudinal Study on Ageing and detailed land use information. We proxy respondents’ exposure to urban green spaces at their residential addresses using street-side and area buffers that take account of the presence of footpaths. Generalised linear models are used to test the association between exposure to several measures of urban green space and BMI.

Results

Relative to the third quintile, exposure to the lowest quintile of urban green space, as measured within a 1600 m footpath-accessible network buffer, is associated with slightly higher BMI (marginal effect: 0.80; 95% CI: 0.16–1.44). The results, however, are not robust to small changes in how green space is measured and no statistically significant association between urban green spaces and BMI is found under other variants of our regression model.

Conclusion

The relationship between urban green spaces and BMI among older adults is highly sensitive to the characterisation of local green space. Our results suggest that there are some unobserved factors other than footpath availability that mediate the relationship between urban green spaces and weight status.

Attitudes and behaviour of general practitioners and their prescribing costs: a national cross sectional survey

BACKGROUND

General practitioner (GP) prescribing accounts for about 10% of NHS expenditure. GPs at the top of the range have annual prescribing costs that are almost twice as much as those at the bottom of the range. This variation cannot be accounted for purely in terms of differences in underlying need for health care.

OBJECTIVES

To describe the relationship between GPs' prescribing costs and their attitudes towards prescribing decisions and prescribing information sources, and to identify potentially modifiable attitudinal and behavioural factors associated with high cost prescribing.

DESIGN

A postal questionnaire was designed on the basis of hypotheses developed from a literature search and an earlier qualitative survey. This questionnaire was sent to a national sample of GPs with equal numbers of practices in the upper, middle, and lowest quintile of prescribing costs.

SETTING

GP practices in England.

PARTICIPANTS

1714 GPs in NHS practice.

OUTCOME MEASURES

GPs' self-reported practices, attitudes and personal characteristics.

RESULTS

There was a 64% response rate. Responders were more likely to be from larger practices, in less deprived areas, and with lower prescribing costs than were non-responders. Multivariable analysis showed that GPs with high prescribing costs were significantly more likely to work in dispensing practices, in practices with low income populations, in single handed practices, and in practices without a GP trainer. They were also significantly more likely to see drug company representatives more frequently, to prescribe newly available drugs more freely, to prescribe more readily to patients who expect a prescription, to report high levels of frustration from lack of time in the consultation, to find unsatisfactory those consultations which ended in advice only, and to express dissatisfaction with their review methods for repeat prescribing. They were significantly less likely to find useful criticism of prescribing habits by colleagues, and to check the BNF rather than other sources when uncertain about an aspect of drug treatment.

CONCLUSIONS

While they cannot be held to have a causal relationship, the pattern of attitudes towards prescribing of GPs in the highest quintile of prescribing costs provide the basis for developing an educational intervention which may be an acceptable method of modifying the attitudes of GPs and consequently reducing their prescribing costs.

A study of factors associated with cost and variation in prescribing among GPs

BACKGROUND

Inappropriate prescribing has the potential to harm both the individual and society. Previous research has identified doctor or demographic characteristics that influence prescribing variation but which were not amenable to change.

OBJECTIVES

To identify modifiable factors associated with GP prescribing variance and cost.

METHOD

Qualitative research methods were used in semi-structured taped interviews with 17 GPs in Avon, South West NHS Region, UK.

RESULTS

GPs considered themselves cautious and conservative prescribers. Prescribing decisions often were justified by the prescriber, despite conflicting clinical or cost arguments. A personally developed drug formulary was used to reduce dilemmas potentially associated with prescribing uncertainty. Willingness to reflect upon, and measure, prescribing habits against set professional standards varied considerably. The absence of monitoring mechanisms of prescribing decisions, coupled with under utilization of the community pharmacist, resulted in uncertain prescribing outcomes. Some GPs found it difficult to keep up to date professionally due to perceived time constraints. Excessive patient demand was considered to influence their prescribing, but GPs stated that they were not unduly influenced by the drug representative.

CONCLUSIONS

Prescribing makes a considerable impact on health and budgets and yet remains a contentious issue. Improved partnerships between patient, doctor and pharmacist must be established. Better prescribing decision monitoring and support through policy development and educational intervention is needed to reduce prescribing uncertainty. Newly established Primary Care Groups may need to reflect upon the difficulties facing prescribers, particularly when prescribing within cash-limited budgets, to avoid discord between prescribing behaviour and local policy development.