Blog Demo Kang Fandi

Teenagers who spend a lot of time planted in front of the TV are more likely to have higher blood pressure, regardless of whether they are overweight. "This is the first research to show a direct and independent connection between TV watching and higher blood pressure among adolescents," said study leader Nicolas Stettler, M.D., M.S.C.E., a pediatric nutrition specialist at The Children's Hospital of Philadelphia.

The team reported on their study of 4,500 American adolescents in the February issue of the Journal of Adolescent Health. They found that sedentary activities and higher body mass index (BMI) were associated with higher systolic blood pressure. Systolic blood pressure is the pressure found when the heart pumps, in contrast to diastolic blood pressure, the pressure between heart beats.

"It was already known that physical activity lowers blood pressure in both adults and children, but sedentary activity is not just the opposite of physical activity," said Dr. Stettler. "For example, other studies have found that decreasing sedentary activity in young people helps prevent or treat obesity better than interventions to increase physical activity."

If further studies confirm these results, encouraging adolescents to reduce their sedentary activity may improve their blood pressure and lower their later risk of cardiovascular disease and stroke.

The researchers studied nationally representative data from 4,500 U.S. adolescents, aged 12 to 19, who participated in the 1999-2002 National Health and Nutrition Examination Survey. Interviewers assessed the adolescents' nutritional intake and activities. Measurements of blood pressure and BMI were adjusted for gender and age.

Within the 12- to 15-year-old age group, the study team found higher blood pressure to be especially associated with higher levels of watching television and video. "Although the association between sedentary activity and systolic blood pressure was rather small, most adolescents spend several hours per day in sedentary activities," said Yasuki Kobayashi, M.D., Ph.D., of the University of Tokyo Department of Public Health, a co-author on this study. "Interventions to decrease sedentary activities may have an important public health impact."

"Elevated blood pressure is one of the most important risk factors for cardiovascular diseases and stroke," said Mr. Takehiro Sugiyama, a medical student at the University of Tokyo and first author on this study. "High blood pressure in adolescents is predictive of hypertension in adulthood, and in addition, adolescent obesity is a predictor or obesity and cardiovascular risk factors in young adulthood and beyond."

The researchers also found that higher BMI is associated with lower diastolic blood pressure, contrary to associations found previously in studies of adults. The implications of this finding are unclear, but shows that adolescents are not just "small adults" and may have determinants of blood pressure that are different from adults said the authors.

Researchers with Deakin's Centre for Physical Activity and Nutrition Research surveyed more than 1200 families to find out if parents had concerns about their children's weight and if they took any preventative action to avoid obesity in their children.

The study of more than 1100 families found that 89 per cent of parents of overweight 5—6 year-olds and 63 per cent of parents of overweight 10—12 year-olds were unaware their child was overweight. It also revealed that 71 per cent of parents of overweight 5—6 year-olds and 43 per cent of parents with overweight 10—12 year-olds did not think their child's weight was a problem.

"These are quite troubling results and suggest that current obesity prevention campaigns are not hitting the mark with parents," said head of the Centre, Professor David Crawford.

"Parents are part of the front line in the battle to reverse the trend of obesity in children, it is therefore essential that they are armed with information and practical strategies that they understand and can easily build into their daily lives."

Professor Crawford said it was not altogether surprising that many parents were unaware their child was overweight given that "many adults are not able to recognise overweight in themselves."

He suggested that some reasons for the lack of recognition of childhood overweight could be that some parents, particularly mothers, tend to judge overweight by whether or not their child is teased about their weight at school or has developed limitations in physical activity; or that, with childhood obesity becoming increasingly normative, that some excess weight simply goes unnoticed.

Despite parents' inability to recognise problem weight in their children, Professor Crawford said a substantial proportion of parents reported they employed various strategies to help prevent their child from gaining too much weight.

The most common strategies included: promoting a balanced diet; promoting physical activity; reducing junk food; limiting the amount of fat and sugar; promoting more fruit.

While this is encouraging, Professor Crawford said that less than 10 per cent of parents increased consumption of fruit and vegetables as a potential weight-control strategy, and few reported that they tried to limit or reduce their child's intake of high-energy drinks and limit television viewing.

Lifestyle changes could improve male sexual function

More than 18 million men in the United States over age 20 are affected by erectile dysfunction, according to a study by researchers from the Johns Hopkins Bloomberg School of Public Health. The prevalence of erectile dysfunction was strongly linked with age, cardiovascular disease, diabetes and a lack of physical activity. The findings also indicate that lifestyle changes, such as increased physical activity and measures to prevent cardiovascular disease and diabetes, may also prevent decreased erectile function. The study is published in the February 1, 2007, issue of the American Journal of Medicine.

"Physicians should be aggressive in screening and managing middle-aged and older patients for erectile dysfunction, especially among patients with diabetes or hypertension," said Elizabeth Selvin, PhD, MPH, lead author of the study and a faculty member in the Bloomberg School of Public Health's Department of Epidemiology. "The associations of erectile dysfunction with diabetes and cardiovascular risk factors may serve as powerful motivators for men who need to make changes in their diet and lifestyle."

For the study, the research team analyzed data from 2,126 men who participated in the National Health and Nutrition Examination Survey (NHANES). Men who reported being "sometimes able" or "never able" to get and keep an erection were categorized as having erectile dysfunction, while men who reported being "always or almost always able" or "usually able" were not.

The overall prevalence of erectile dysfunction among men in the United States was 18 percent. Men aged 70 and older were much more likely to report having erectile dysfunction compared to only 5 percent in men between the ages of 20 and 40. Nearly half of all men in the study with diabetes also had erectile dysfunction. And, almost 90 percent of all men with erectile dysfunction had at least one risk factor for cardiovascular disease, including diabetes, hypertension, having poor cholesterol levels or being a current smoker. Men with erectile dysfunction were also less likely to have engaged in vigorous physical activity within the month prior to participation in the study.

Researchers have discovered that taking calcium and vitamin D supplements while on a weight loss program lowers the risk of cardiovascular disease.

The scientists enrolled 63 women with a body mass index over 30 on a 15-week low-calorie diet. At the start of the experiment, the women's daily calcium intake was 700 mg on average, well below the 1,000 mg recommendation. "This is nothing exceptional," points out Dr. Angelo Tremblay, who led the study. "More than 50% of women don't get the daily recommended dose."

In addition to the low-calorie diet, participants were given daily tablets containing either a placebo or 1,200 mg of calcium with vitamin D "to facilitate calcium absorption," adds Dr. Tremblay. At the end of the 15-week period, researchers observed greater drops in LDL (bad cholesterol) and increases in HDL (good cholesterol) in the calcium-plus-vitamin D group than in the placebo group.

Researchers also observed that the amount of weight lost during the 15 weeks did not seem to have an impact on the improvement seen in cholesterol levels. This suggests that calcium and vitamin D supplementation might also lower cardiovascular risk in women with low calcium intake as it does with women on a diet.

The authors conclude that prescribing calcium and vitamin D supplements should be considered as a component of weight loss programs aimed at people with insufficient calcium intake.

Professor Tremblay and his team have been studying the relationship between calcium and obesity for the past six years. Their first results, published in 2003, revealed that people with low calcium intake have a higher fat percentage, wider waists, and higher bad cholesterol levels than people whose calcium intake is moderate or sufficient. A second study, spanning over six years, showed that people who reduced their dairy consumption during that period gained weight, and saw an increase in body fat percentage and waist size.