Height and IQ likely linked, says study of DNA

They are prone to paranoia and poor mental health and tend to be jealous lovers. Now it seems the vertically challenged can also suffer from low intelligence, according to scientists.

Academics in London and Edinburgh claim people who are shorter than average are more likely to have lower IQs than their taller counterparts, after they identified genes that influence height and IQ. Unlike previous studies, which explored the link in family members, theirs is the first to analyse DNA markers in a large sample of more than 6800 unrelated people.

‘‘What we found was a small association between height and intelligence such that people who are taller tend to be smarter,’’ said Riccardo Marioni, from Edinburgh University.

The assertion is certain to be disputed by millions of people in Britain who fall short of the average height, which for men is 5ft 9in and for women 5ft 4in.

Nevertheless, studies have claimed that smaller people are more likely to suffer from poor mental health. Recent research by Oxford University claimed that shortman syndrome – popularly known as the Napoleon complex – does exist, making some such people paranoid, distrustful and scared of others.

Marioni and colleagues from Aberdeen University and University College London based their findings on data compiled from people recruited between 2006 and 2011 for the Scottish Family Health Study. Intelligence was determined by tests that measured linguistic ability, powers of recall and reaction times.

The team concludes that ‘‘in this study we found a moderate and statistically significant genetic correlation between height and general intelligence’’. They believe that about 70 per cent of the link can be explained by genetics and the rest by environmental influences.

Scientists believe that understanding the genetic correlation between height and IQ could help to predict people’s health problems.

Previous studies have linked short stature to a heightened risk of cardiovascular disease. Studies have claimed that men who are about 5ft 4in tall are about 50 per cent more likely to be jealous and distrustful of their partners than those who are 6ft 6in.