Short men and overweight women tend to be less well-off, and for once, scientists say this is not necessarily the result of poor life choices, but of genetics.
A study published in the BMJ by scientists from the University of Exeter investigates how people's size impacts on their socio-economic well-being. A lot of research had already been dedicated to the topic in the past, with evidence of a strong association between size, weight and social status.
In the publication, the conclusion was that people from poorer backgrounds were less likely to grow tall and more likely to put on weight because they were less educated and had more problems getting a balanced nutrition.
"Chicken and egg" question
This time, researchers decided to turn the problem around, and looked at 396 genetic variants of height and 69 variants of Body Mass Index of 120,000 participants in the UK Biobank.
"It is a classic chicken and egg question. By looking at genetic variants, we wanted to assess whether being just a little a bit shorter or fatter could impact your socio-economic status, without other factors coming into play", Jess Tyrrell, co-author of the study, told IBTimes UK.
They analysed how the participants who presented the different genetic variants fared in terms of five socio-economic measures. These included if they had a degree, and if they didn't, how long they had been in full time education, if they were employed, what their job was, and how much they earned annually.
Strictly looking at genetics allowed the researchers to better understand the link with socio-economic factors. "Genetics gives us the opportunity to look at the causes in a more straightforward manner than in an observational study, where many factors can interfere" says Tyrrell.
Lower income and job status
She and colleague Timothy Frayling found strong evidence that being short or overweight, for no other reasons than genetics, led to poorer conditions of life and to a lower socio-economic status. This was particularly true for height: shorter participant were less well-off according to every socio-economic indicators used by the scientists.
In terms of weight, a high BMI was strongly associated to lower income and measure of deprivation (employment status, car or house ownership...). For example, if a woman was a stone heavier (6.3kg) simply because of her genetics, she would earn £1,500 less annually than a comparable woman of the same height who was a stone lighter.
The study's authors believe the reason for this relationship should now be investigated, to combat any form of discrimination, conscious or unconscious, against people who are not as tall or as slim.
"We need to see scientists from other field, psychologists and economists in particular, to study the causes behind our results. Economy experts could look for example at how obesity reduce productivity and leads to poorer economic conditions", says Tyrrell. She hopes that on the long term, such studies will be able to inform policies, so that people do not suffer from their genetics.