Obesity rates have escalated dramatically in the last several decades and the condition negatively affects health, but its connection to conditions such as cardiovascular disease (CVD) is complex and not fully understood. In the March issue of the Journal of Investigative Medicine experts say more research is needed to discover the links between obesity and CVD, with particular attention to biological differences between women and men.

The report stems from a multidisciplinary workshop of obesity and heart disease experts, convened by the Society for Women’s Health Research to address the National Institutes of Health Obesity Research Task Force’s report on the need for future research into obesity. The workshop focused on developing ideas for future research on sex differences in obesity and CVD.

“The task force report included sex as a population variable, but it did not explicitly recommend further research into biological sex differences in obesity and related diseases,” said Sherry Marts, Ph.D., one of the report’s authors and vice president of scientific affairs for the Society, a Washington, D.C., based advocacy organization. “We know that weight gain and fat deposition differ between women and men. Research into these differences can generate tremendous information about the development and progression of disease.”

The workshop participants developed three recommendations.

First, future research is needed to investigate adipose tissue (AT) composition and distribution. AT stores fat and responds to the body’s need for energy by mobilizing fat. AT also produces chemical signals that are involved in regulating appetite. Its distribution plays a major role in CVD risk.

In humans, the primary regions containing AT as subcutaneous fat are the hips, buttocks and thighs, while visceral fat is found in deeper deposits of the abdominal cavity. There is an important sex difference in AT distribution, as studies have shown that the storage of AT in visceral depots is linked to a higher risk of CVD in women. In other words, if a woman stores a lot of AT (and therefore a lot of visceral fat) around her waist, she may have an elevated risk of developing CVD. That theory is controversial, however, and some researchers believe that increased visceral fat is not a risk factor for CVD, but a marker of CVD’s progression in one’s body.

Another area that the experts agree requires further research is studies throughout the lifespan of women and men.

Appropriately designed longitudinal studies can help explain variances among women and men, different ethnicities and socioeconomic groups. These studies can examine sex differences in the critical periods of a woman’s life, especially those associated with dramatic hormonal change such as the onset of menstruation, pregnancy and menopause, which can impact the risk of weight gain, obesity and the development of other risk factors for CVD. Longitudinal studies may also shed light on why women experience CVD on average 10 years later than men.

A third recommendation of the workshop was the need to refine current and develop new tools of measurement to study energy intake, energy expenditure, weight gain, obesity, and CVD risk in animals and humans. Current measurements are not well standardized and are not always sex-appropriate, making it difficult for researchers, especially those from different disciplines, to draw accurate conclusions.

“Obesity has become a pandemic,” Marts said, “and its impact on health is broad, complex and varied depending on the individual. That’s why we need an interdisciplinary approach that takes into account factors like sex. This will remain an important area of study for decades to come, as heart disease is the number one killer of American women and men.”

The reports’ other authors are Eileen M. Resnick, Ph.D., Viviana R. Simon, Ph.D., and Sara O. Iskikian, M.S., all from the Society for Women’s Health Research. The workshop took place in Washington, D.C., in November 2005.

Citation: Eileen M. Resnick, Viviana R. Simon, Sara O. Iskikian, and Sherry A. Marts. “Future Research in Sex Differences in Obesity and Cardiovascular Disease: Report by the Society for Women’s Health Research,” Journal of Investigative Medicine, Volume 55, Issue 2, March 2007, Pages 1-11.

Source: Society for Women’s Health Research (SWHR)