“observational analyses are limited by reverse causality — meaning that if an association between sleep habits and pad is found, we cannot be certain if sleep habits caused pad or having pad caused the sleep habits,” yuan said. “mendelian randomization is a robust method for evaluating causality and provides more certainty about the results.”
less than five hours of sleep, nearly double the risk of pad
according to their observational analysis, the strongest causal relationship exists between short sleep and pad, where the relationship goes both ways. they found that the 53,416 adults in the study who slept less than five hours per night had nearly double the risk of pad compared to those who obtained a solid seven to eight hours of rest. further analysis involving subject pools of 156,582 and 452, 028 people supported this finding.
because the relationship goes both ways, pad was also associated with an increased likelihood of a short night’s sleep. “the results indicate that brief nighttime sleep can raise the chance of developing pad and that having pad increases the risk of getting insufficient sleep,” said yuan.
when the team performed an observational analysis of long sleep (defined as eight or more hours per night), they found that the 53,416 adults they looked at had a 24 per cent greater risk of pad compared to those getting to seven to eight hours of nightly rest. the finding was supported in two other population samples, but no causal relationship was found the two variables.