Researchers report a link between sleep duration and increased risk of high blood pressure — but only in women.

The study included 3,027 cardiovascular disease-free, middle-aged white men (43.5 percent) and women (56.5 percent). High blood pressure was defined as systolic pressure of 140 millimeters of mercury (mm Hg) and above, or diastolic pressure 90 mm Hg and above, or use of anti-hypertensive drugs.

The researchers compared short duration (less than 6 hours) to mid-level (6–8 hours) of sleep and calculated participants’ odds of developing high blood pressure, while accounting for many potential disease predictors including marital status, income, education, physical activity, smoking and others.

Researchers found:
• Short duration of sleep was associated with a significant increased risk of high blood pressure in women compared to sleeping 6–8 hours per day.
• No significant association was seen in men.
• Sleep’s effect was stronger in pre-menopausal women than post-menopausal women.

By increasing the risk of high blood pressure, sleep loss may lead to cardiovascular disease in women, researchers said. But prospective and laboratory evidence is necessary to support the association.

(Note: Actual presentation time is 6 p.m. ET, Wednesday, March 11, 2009)

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Abstract P343 – Poor sleep quality may put children at risk for obesity
In a study of 967 students (430 girls, 537 boys) 9 to 14 years old, researchers gathered data on sleep behaviors and measured height and weight to calculate body mass index (BMI). Using parental questionnaires, sleep difficulties were classified as “often” or “sometimes” based on whether a child had one or more sleep problems. Standard age- and sex-specific height and weight measures determined BMI status. Overweight is defined as a BMI of 25 to less than 30 and obesity is defined as a BMI of 30 or greater.

Researchers found that among the participants:
• Childhood overweight was 22 percent.
• Childhood obesity was 10.3 percent.
• Sleep problems “often” occurred in 36 percent.
• Compared to those “never” or “sometimes” having sleeping problems, children having problems “often” had 62 percent higher odds of being obese.

Potential confounding variables included child gender, age, mother’s marital status, ethnicity and family income. No interactions were found between sleeping problems and current smoke exposure.
“Poor sleeping quality is associated with childhood obesity, but further study should focus on the direction of the association,” researchers said.
(Note: Actual presentation time is 5 p.m. ET, Friday, March 13, 2009.)

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Abstract P370 – Stress plus poor sleep quality may increase obesity in African Americans
Psychosocial stress appears to strengthen an inverse correlation between sleep quality and obesity in African Americans, new research suggests.

In a study of 1,515 African-American residents of Atlanta, ages 30 to 65, researchers measured body mass index and computed global sleep quality scores (healthy sleep, poor sleep, chronic sleep disorder). Individual Pittsburgh Sleep Quality Index (PSQI) scores also were evaluated.

General perceived stress was derived according to a standard scale and divided into thirds to test interactions. “Covariates” included age, gender, physical activity, smoking, socioeconomic status and cardiovascular disease.

“After multivariate adjustment, sleep quality as assessed by global sleep quality score showed no association with obesity (odds ratio 1.02),” the researchers said. Nevertheless, general perceived stress “positively interacted with global sleep quality to significantly increase the likelihood of obesity in people with poor sleep quality.” Stress also interacted with two PSQI domains — “daytime dysfunction” and “sleep latency” — to increase the likelihood of obesity.

“We found that poor sleep quality increases the likelihood of obesity, and this association is positively modulated by perceived stress,” researchers said. “Previous results and ours may suggest an issue of sensitivity of the PSQI scale or of severity of sleep disease.”

(Note: Actual presentation time is 5 p.m. ET, Friday, March 13, 2009.)

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