Are good neighbours really life-savers?

“Having good neighbours can help cut heart attack risk,” reports The Independent.

The paper reports on a nationally representative US study of over 5,000 adults over the age of 50.

People were asked about how they rated their neighbourhood social cohesion, then followed up for four years to see if they had a heart attack.

Social cohesion refers to how “neighbourly” people feel, and relates to feelings of security, connection to the area and trust of inhabitants. In this study, social cohesion was assessed by asking people how much they agreed with simple statements such as “people in this area are friendly” and “people in this area can be trusted”.

The study found that higher social cohesion was associated with a reduced risk of heart attack.

However, the association became non-significant (could have been the result of chance) once the researchers adjusted for all factors known to be associated with heart attack risk, such as smoking history, exercise and body mass index (BMI).

This makes it more difficult to draw any meaningful interpretation from these results. It's likely that any link between the risk of a heart attack and perceived social cohesion is being influenced by a varied mix of other factors.

While building social connections can bring mental health benefits, relying on your neighbours to cut your risk of a heart attack is probably unwise.

Where did the story come from?

The study was carried out by researchers from the University of Michigan. Sources of funding were not reported. 

The study was published in the peer-reviewed Journal of Epidemiology & Community Health.

This story was covered by The Independent, the Mail Online and The Daily Telegraph.

It was not stated that the association between social cohesion and heart attack was no longer significant when all covariates were adjusted for.

However, the Telegraph did make the point that it is too early to make any definitive conclusions.

What kind of research was this?

This was a cohort study that investigated whether higher perceived neighbourhood social cohesion was associated with lower incidence of heart attack (myocardial infarction).

Cohort studies cannot show that higher social cohesion caused the reduction in heart attacks, as there could be many other factors responsible for any association seen.

What did the research involve?

The researchers analysed 5,276 people without a history of heart disease who were taking part in the Health and Retirement Study – a nationally representative study of American adults over the age of 50.

People were asked at the beginning of the study about how they rated their neighbourhood social cohesion. Social cohesion was measured by the participants’ agreement with the following statements:

• “I really feel part of this area”
• “If you were in trouble, there are lots of people in this area who would help you”
• “Most people in this area can be trusted”
• “Most people in this area are friendly”

There was then a follow-up period of four years to see if those studied had a heart attack, which was self-reported or reported by a proxy if the participant had died.

The researchers looked to see if people with higher perceived social neighbourhood cohesion had a reduced risk of heart attack.

What were the basic results?

During the four-year study, 148 people (2.81%) people had a heart attack.

Each standard deviation (a measure of variation from the average) increase in perceived neighbourhood social cohesion was associated with a 22% reduced odds of heart attack after adjusting for age, gender, race, marital status, education and total wealth (odds ratio [OR] 0.78, 95% confidence interval [CI] 0.63 to 0.94).

However, the association was no longer statistically significant if all potential confounders were adjusted for (age, gender, race/ethnicity, marital status, education level, total wealth, smoking, exercise, alcohol frequency, high blood pressure, diabetes, BMI, depression, anxiety, cynical hostility, optimism, positive affect, social participation and social integration) (OR 0.82, 95% CI 0.66 to 1.02).

The researchers also divided perceived neighbourhood social cohesion into four categories: low, low-moderate, moderate-high and high. When age, gender, race, marital status, education and total wealth were adjusted for, people with high perceived neighbourhood social cohesion were at reduced risk of heart attack compared to people with low social cohesion. Again, this association was no longer significant if all confounders were adjusted for.

How did the researchers interpret the results?

The researchers concluded that “higher perceived neighbourhood social cohesion may have a protective effect against myocardial infarction”.

Conclusion

This US cohort study found that higher social cohesion was associated with a reduced risk of heart attack. However, the association became non-significant once the researchers adjusted for all behavioural (such as smoking or exercise), biological (such a BMI) and psychosocial (such as depression) factors that could act as potential confounders.

It is difficult to draw any meaningful interpretation from these results. Perceived social cohesion in this study was only measured by asking people how much they agreed with four simple statements about whether they liked living in the area, whether people in the area were friendly and if they could be trusted. This tells us little about the sociodemographic structure of the area, or the individuals’ interpersonal relationships with others.

Also, despite the large initial sample size, there were relatively few heart attacks over the four years. Heart attack cases were also noted by individual or proxy-self report, rather than a review of medical records, which may also have led to errors.

There are a variety of biological, hereditary and lifestyle factors that are well known to be associated with greater risk of cardiovascular disease, and various other psychological ones that have been speculated (such as stress).

As the results of this study suggest, it is likely that any link between risk of heart attack and perceived social cohesion is being influenced by a varied mix of other factors.

If you want to try and reduce your risk of a heart attack, maintaining a healthy weight through diet and exercise, avoiding smoking and limiting alcohol intake are a great start.