By surveying the retail outlets that may reflect the state of peoples’ health in cities and towns, the RSPH published a league table of healthy and unhealthy shopping regions . In our study, we found a person volunteering to be tested in a heath check Pop-Up in one of the unhealthy regions defined by the RSPH report is more likely to have suspected or diagnosed elevated BP compared to an age-similar person tested in a healthy town/city and this is our principal finding. Moreover, a measure of unhealthy retail outlets within a shopping centre was significantly associated with detection rate of suspected or diagnosed elevated BP in our sample. In other words, the proportion of fast-food takeaways, bookmakers, tanning salons and payday loan outlets within a shopping centre is related to the number of cases of elevated BP in people volunteering to be examined as part of a Pop-Up health check conducted in the shopping centre. Our findings add to the knowledge of potential methods of assessing people at risk of hypertension and reveal an interesting link to location of testing.
Relationships between shopping environment and health have been documented in the research literature. For example, data from a population health survey of 2900 adults was linked with geographic measures of access to food retailers in Edmonton in Canada. Results indicated the ratio of fast-food restaurants and convenience stores to grocery stores and produce vendors near people’s homes was related to likelihood of being obese . Other research from the United States supports the claim that access to fast-food restaurants is associated with obesity among adults , excess weight gains over time  as well as insulin resistance . There is also good evidence to show that excessive use of fast-food restaurants is associated with higher BMI in children in the UK . The RSPH report highlighted the importance of ensuring retail areas encourage healthy lifestyles and suggested businesses such as fast-food outlets, betting shops, and payday lenders should be unable to cluster in areas of high deprivation . Therefore, we believe our measure of an unhealthy shopping environment to be a reasonable one. For example, payday lending is a contemporary public health concern because of the vulnerability of the populations using these lenders and the documented detrimental effect that financial difficulties can have on mental and physical health . Moreover, there is a strong association between a profusion of betting shops and problems with gambling and poor health indices . Sunbed use is associated with a significant increase in risk of melanoma  and at least one systematic review has shown that the typical sunbed user is more likely to have an unhealthy diet, smoke and drink alcohol more frequently than a non-user .
To our knowledge the idea of a Pop-Up health check for BP, set in a shopping centre, has not been previously explored. Pop-Up clinics have been proposed and examined for HIV testing  and there are several reports on the effectiveness of mobile health clinics designed to raise awareness and screen for a wide variety of conditions, such as, colorectal cancer , paediatric eye disorders  and general health in vulnerable populations . Moreover, mobile health clinics are widely used in the US and, for example, one extensive study has found them to be effective for screening for suspect hypertension . Interestingly, using the Pop-Up concept to improve public health has recently been extended to the idea of temporary urban Pop-Up parks designed to solve the limited access to public physical activity recreation spaces many urban residents face . Our novel idea of a Pop-Up health check in a shopping centre certainly fits with a recent call by NHS England and Public Health England, urging council public health teams to organise BP check opportunities in public places .
Around one half of all cases reported in this study were already aware of having elevated BP, or self-reported some history of issues with elevated BP. The effect we detected between the unhealthy and healthy shopping regions could therefore be explained by differences in undiagnosed hypertension/suspected hypertension or be explained by differences in possible poor control of known hypertension/suspected hypertension; as likely, the effect could be explained by a combination of the two factors. Overall numbers were not substantial enough for us to make a distinction between these two factors. Yet this distinction is important. One centres on medication adherence and long-term management issues, whilst the other centres on detection. Both have substantial public health importance and their relationship with socioeconomic status should be studied further, as suggested by other reports .
There are some critical limitations to our observations. For example, there are ethnic differences in the prevalence of hypertension but we did not record or report our participants’ ethnicity. Prevalence of hypertension is raised in South Asian, Afro-Caribbean, and West African people in England and ethnicity is an important consideration in assessing BP measures in community-based studies . We therefore cannot comment on a bias that might be introduced by some areas having higher prevalence of different ethnic groups compared to others. Similarly, a bias in our results may have been introduced by differences in levels of obesity between ‘healthy’ and ‘unhealthy’ locations or differences in ‘white coat’ hypertension whereby the clinical setting precipitates artificially elevated BP due to increased patient anxiety .
Furthermore, a diagnosis of elevated BP cannot be made from measurements at a single point in time. One author (LAE) performed most, but not all of the testing so our results might be limited by the use of different assessors. Nevertheless, other discrepancies in measurement from, for example, failure to position participants and their arms consistently would have been minimised by the identical testing environment afforded by the purpose-built Pop-Up. An unavoidable limitation of the results from our case finding exercise arises from only being able to assess individuals interested in having their BP measured. Moreover, we originally aimed to test only people who were > 40 years but the Pop-Up generated a lot of interest and we examined younger people too; consequently, around one quarter of our participants were younger than 40 years. Our study design meant our results are limited to observational associations. Moreover, our study did not have a longitudinal element where we could, for example, follow-up the suspected cases. In addition, whilst our unhealthy retail outlet score is based on a previous report  it is very much a surrogate measure and has not been validated in other studies.
There is more to understand about different ways to case-find suspect hypertension. A proven effective route is to create easily accessible testing opportunities such as in community settings or the workplace  . There are other advantages to screening for hypertension away from a ‘white coat’ medical environment . Of course, these forms of testing are still restricted to individuals who volunteer to have their BP measured and current evidence is insufficient to recommend specific approaches for community-based case finding for elevated BP . Nevertheless, our study contributes a modest example of a new approach to assessing BP outside primary care. The health check Pop-Up also offers a way of educating the public about hypertension and BP. Our results also imply that an in situ public health check might benefit from a targeted strategy, not seen in current approaches . We assessed 351 people in only 7 days of testing, a remarkable number given the tests of eye health carried out on the same day.