US researchers, who tracked more than 100,000 Americans over 15 years, found a worrying link between the behaviours. US researchers, who tracked more than 100,000 Americans over 15 years, found a worrying link between the behaviours.
US researchers, who tracked more than 100,000 Americans over 15 years, found a worrying link between the behaviours. US researchers, who tracked more than 100,000 Americans over 15 years, found a worrying link between the behaviours.