Islamabad - Napping for an hour or more each day and extreme sleepiness raises the risk of developing diabetes, new research suggests.

Although recent evidence has suggested that a daily nap could improve health and help people live longer, it seems that dozing for too long may actually by harmful. Scientists from the University of Tokyo are unsure whether it is the napping itself or an underlying condition which makes people more sleepy that is driving the effect.

After examining more than 200 studies involved 261,000 participants, they found that severe daytime fatigue was associated with a 56 per cent increased risk of developing diabetes.

And taking a regular daytime nap for an hour or more was found to increase the risk of developing the condition by 46 per cent. Author Dr Tomohide Yamada, from the University of Tokyo, Japan, said: “Excessive daytime sleepiness and taking longer naps were associated with increased risk of type 2 diabetes, with a short nap not increasing this risk. “Daytime napping might be a consequence of night-time sleep disturbance such as obstructive sleep apnoea.

“Epidemiological studies have shown that obstructive sleep apnoea is independently linked to blockages (ischaemia) of heart arteries, stroke, fatal and non-fatal cardiovascular events, and all-cause mortality.”

Around 3.9 million people are thought to have diabetes in Britain, of which 600,000 are currently undiagnosed. Cases in England and Wales have risen by 59.8 per cent in the past decade - as an additional 1.2 million adults are now living with the condition compared to ten years ago. Dr Yamada continued: “Several studies have demonstrated the beneficial effects of taking short naps less than 30 minutes in duration, which help to increase alertness and motor skills.

“A short nap finishes before the onset of deep slow-wave sleep. “Entering deep slow-wave sleep and then failing to complete the normal sleep cycle can result in a phenomenon known as sleep inertia, in which a person feels groggy, disoriented, and even sleepier than before napping.

“Although the mechanisms by which a short nap might decrease the risk of diabetes are still unclear, such duration-dependent differences in the effects of sleep might partly explain our findings.” The research was presented at the European Association for the Study of Diabetes annual conference in Stockholm.

Teens copy parents’ smoking: study

Although many teens don’t often copy their parents’ behaviour, there’s one habit they may pick up from mom or dad — smoking. Teens are three times more likely to smoke at least one cigarette — and their odds of nicotine dependence are nearly twice as high — if one of their parents is dependent on nicotine, the new study found.

And teenage daughters of women who smoke seem to be most at risk. These young girls were almost four times as likely to be dependent on nicotine if their mother was a regular smoker, the researchers said.

“Most smokers start smoking when they are teenagers. As this study shows, parents are a powerful influence,” the study’s lead author, Denise Kandel, a professor of socio-medical sciences in psychiatry at Columbia University Medical Centre and the Mailman School of Public Health in New York City, said in a university news release.

“To prevent teens from starting to smoke and becoming addicted to tobacco, we need to do a better job of helping parents quit smoking,” she said.

The study included data from the US National Survey on Drug Use and Health collected between 2004 and 2012. Researchers reviewed information on the smoking habits of 35,000 sets of parents and their teenage kids.

Of the teens whose parents never smoked, 13 percent said they smoked at least one cigarette in their lifetime. In contrast, of the teens that had a parent that was dependent on nicotine, 38 percent said they smoked at least once, the study revealed.

When the researchers only considered the teens that admitted to smoking at least one cigarette, they found 5 percent were dependent if their parent didn’t smoke, and 15 percent were dependent if their parent was hooked on cigarettes.

Girls didn’t seem to be more likely to become dependent if their father smoked, and whether or not a parent smoked didn’t seem to impact the risk of tobacco dependence for boys, the researchers said. The study authors suggested that reaching out to parents and educating them about smoking and its effects on their kids during pediatrician visits might help give parents a reason to try to quit.