Are you one of those Canadians pleading for Mr. Sandman to bring you a dream? You are not the only one counting sheep in a desperate bid to fall asleep, Statistics Canada says.

One in every seven Canadians aged 15 or older -- about 3.3 million of us -- have trouble going to sleep or staying asleep, according to a study released by Statistics Canada on Wednesday.

The study, based on data from the 2002 Canadian Community Health Survey (CCHS), found that just under one-fifth of these insomniacs average less than five hours of sleep a night.

In contrast, only two per cent of people who did not have insomnia reported less than five hours of sleep per night.

Respondents who told the CCHS that they had trouble going to sleep or staying asleep "most of the time" or "all of the time" were considered to have insomnia.

Moreover, the study echoes earlier research that found close ties between insomnia and stress, as well as chronic conditions that involve pain.

"The CCHS found that people with chronic health conditions were likely to report insomnia. For example, in 2002, more than one-fifth of people with asthma, arthritis or rheumatism, back problems or diabetes reported insomnia," Statistics Canada reports.

Among people who did not have these conditions, only 12 per cent reported insomnia.

Life stress also kept Canadians up at night, the study says. Nearly one-quarter (23 per cent) of people who described most of their days as being either "quite a bit" or "extremely" stressful reported insomnia.

This was more than twice the proportion among people who reported little or no life stress.

Though work stress appeared to be associated with insomnia, when factors such as chronic pain, obesity, and life stress were taken into count, that link was discounted.

However, one's work schedule did play a role with insomnia.

"Even accounting for chronic pain and the other factors, the odds that shift workers would report insomnia were high compared with other workers," the study says.

Obesity and middle age

Statistics Canada also reports that there are less obvious factors that contribute to insomnia.

When physical and mental health, lifestyle and socio-economic factors were taken into account, Statistics Canada reported finding that there are less-obvious factors that contribute to insomnia.

"The study showed that middle-aged people (ages 45 to 64) had high odds of suffering from insomnia, as did people who were widowed and people with low education," the study says.

Weight also played a contributing role. When chronic conditions and other variables were taken into account, individuals who were extremely obese had higher odds of reporting insomnia than those of normal weight.

Statistics Canada says this link could be related to sleep apnea, which is related to obesity and is considered to be a risk factor for insomnia. However, the correlation cannot be drawn from this study as sleep apnea was not measured.

The agency says that individuals who are considered extremely obese have a body mass index of 35 or more, while those of normal weight have a BMI of 18.5 to 24.9.

The prevalence of insomnia also rose with age.

While about 10 per cent of people aged 15 to 24 reported suffering from insomnia, this proportion doubled to almost 20 per cent among people aged 75 or older.

However, when the agency took into account that old age is associated with the presence of chronic conditions, they determined that the prevalence of insomnia among seniors was largely attributable to poorer health, not age.