54 years is the male life expectancy in the Republic of the Congo, Papua New Guinea, and the Calton area of Glasgow. The excess mortality in Glasgow and West Central Scotland in general which leads to such stark statistics has been dubbed the Glasgow Effect. Excess is the key word though – these are deaths, especially early deaths, which cannot be explained by the usual culprit of socioeconomic deprivation. As such, the Glasgow Effect is a much smaller problem than the nationwide health inequalities that result from inequality and deprivation. But because there is no obvious explanation for it, numerous researchers in Glasgow are on the case.
A Tale of Three Cities
It was the best of times, it was the worst of times – Glasgow in the 1970s had comparatively low excess mortality to other cities, but was suffering the collapse of heavy industry, and the beginnings of neoliberal economic policy. Since then, the ‘mortality gap’ has grown. Comparable cities haven’t suffered the same unhealthy fate though – Liverpool and Manchester have almost identical levels of deprivation, and had similar levels of heavy industry and aversion to Thatcherism, but when the three cities are compared, Glasgow has 15% more deaths, and 30% more deaths under the age of 65. Any potential explanation of the Glasgow Effect must therefore rely on a set of factors which are systematically different in Glasgow.
This is where a lot of potential explanations fall down, as a lot of them are closely linked to the deprivation profile, which doesn’t vary between the cities. Immediate causes of ill health like smoking being more prevalent in Glasgow don’t offer a satisfying explanation either, as they simply shift the causation question back, to ask why smoking is more prevalent in Glasgow. A full explanation must include factors which could feasibly contribute to worse health behaviours in the first place.
Why does it always rain on me?
One unlikely candidate is the weather (well it would explain why the British are obsessed with it). Scotland, particularly the West, is one of the wettest places in Europe. Glasgow’s reputation as being wetter than other cities is borne out by the climatic data – Abbotsinch gets 1080mm per year, with Paisley getting 1200mm, compared to 700mm falling on Edinburgh. Liverpool averages 700-850mm per year, with Manchester getting 800mm. The additional rainfall means that Glasgow gets fewer hours of sunshine too. An increase in Glasgow’s rainfall since 1971 even correlates with the emergence of the Glasgow effect.
Sunshine on Leith
But correlation doesn’t equal causation. How does the climate affect health? One theory on the link is being researched in Glasgow. It focuses on sunshine, which the skin uses to synthesise vitamin D. As well as rickets, low levels of vitamin D have been linked with chronic disease and mortality. We can’t get enough from our diet (oily fish and eggs are good though), and if the climate isn’t conducive to sunbathing, this may contribute to the majority of the population being vitamin D deficient. As well as getting less sunshine, the greater cloud cover in the West of Scotland means that less UV light makes it through, which may make things worse (true to form, despite lower UV levels, Scotland manages to have higher than the UK average of skin cancer rates). To link vitamin D deficiency to the Glasgow Effect, a link with premature mortality would need to be established. This is the aim of a current research project at the Glasgow Centre for Population Health.
An element of the link between vitamin D and health may be due to low levels being a marker of other risk factors, like obesity and inactivity. These factors shift the mechanism from being purely physical to involving behavioural factors too. But these behavioural factors could also be being influenced by the weather. This is straying from established theories, but existing evidence can be applied to the context of the Glasgow Effect.
Glasgow Smiles Better?
Seasonal Affective Disorder (SAD) is a prime example of how the environment can affect our health. In the winter months, susceptible individuals get depressed due to the lack of natural light available. Naturally, the further north you live, the more likely you are to develop SAD, but this correlation is surprisingly weak. Stronger links have been shown to exist between climatic variables like hours of sunshine and cloudiness. If this applies in Glasgow, a higher incidence of SAD would be expected. As well as the toll on mental health, higher levels of SAD would explain some of the worse physical health – SAD is associated with weight gain and inactivity. The bulk of Glasgow’s extra rainfall comes from autumn to spring – in the winter it gets around twice as much precipitation than Liverpool and Manchester. It looks like a perfect storm for SAD.
The neurotransmitter serotonin is thought to underlie the mechanism by which SAD progresses. Associated with mood and wellbeing, serotonin is transported away from the brain more in winter. This process is decreased the more hours of sunshine there are, and increased the more humid it is.
Under the weather
Other neurotransmitters may equally play a role in the climate’s effect on health. Endorphins are released by, amongst other things, prolonged exercise and exposure to sunlight. Glasgow’s excess rainfall and sunshine deficit hardly encourage exercise. An endorphin deficit has a number of negative effects on health. Endorphins along with oxytocin act as an appetite suppressant, especially against salty food. There is evidence that endorphins have a direct effect on the immune system – beta-endorphin has been shown to produce natural killer cells, which kill cancer cells and slow the ageing process. In addition, if Glaswegians did have lower levels of endorphins, they’d be missing out on the pain relief and feeling of wellbeing they provide.
There are other ways of releasing endorphins, but they aren’t nearly as healthy. Eating sweet, carbohydrate-rich food like chocolate is one of them. A more drastic measure is to take artificial opiates, which include drugs like heroin and methadone. Drug abuse is heavily involved in the premature deaths which contribute to the Glasgow Effect. It’s also feasible that comfort eating (and drinking) increase when the weather is bad. It’s fairly speculative to link climate to drug abuse, but the theory, like the others above, is testable – do Glaswegians have lower levels of vitamin D/serotonin/endorphins?
So is living in Glasgow harmful to health? To the extent that the weather is to blame, there are ways of minimising its impact. Some common sense tips would be to make the most of the sun when it’s out (without getting sunburnt), and to keep active and outdoors especially during the winter – Glasgow has (or at least used to have) more parkland per head of population than any other city in Europe, so there’s no excuse not to. Going on holiday during the winter makes a lot of sense too.
It would be fascinating if a link were to be discovered between Glasgow’s climate and the Glasgow Effect, but this would still only concern the excess mortality compared to Liverpool and Manchester. Even if the Glasgow Effect was eradicated, Glasgow would remain one of the unhealthiest cities in the UK. This much bigger health deficit compared to other parts of the country is attributable to deprivation and inequality, which must be reduced if Glasgow’s health is to improve.