December 2004: The Year in Review -- Ob/Gyn & Women's Health

Ursula Snyder, PhD


January 24, 2005

Women's Health - Obesity

Obesity, taking 400,000 lives a year, threatens to supersede smoking as the leading cause of death in the United States. The Centers for Disease Control and Prevention (CDC) has reported that two thirds of Americans are overweight or obese; 31% meet the criteria for obesity.[2] Over the past 30 years -- between 1971 and 2000 -- Americans have significantly increased their caloric intake; women have increased their intake by 22% (nearly 3 times the 7% increase by men).[3] On average, women consume 1877 calories/day, although the current recommended intake is 1600 calories/day. A report jointly produced by the American Public Health Association, the United Health Foundation, and the Partnership for Prevention cites a 97% increase in obesity between 1990 and 2003.[4] The incidence of obese women in the United States stands now at about 33% of the population; it has practically doubled within a single decade.

Research on women and obesity published this past year is distressing. Indeed, the just published 24-year follow-up of the Nurses Health Study indicates that obesity and reduced physical fitness are strong and independent predictors of mortality in women.[5] (See Medscape Medical News CME story.) Obesity and low physical activity are also strong and independent risk factors for endometrial cancer.[6] It has also been found that obesity increases by nearly 2-fold the risk of acute myelogenous leukemia (AML) in older women.[7] The authors of this study suggest that the population-attributable risk of AML due to obesity could approach 30% in the United States. Data presented at the 2004 annual scientific meeting of the American College of Gastroenterology cited a 4-fold increase in the risk for colon cancer among obese women compared with women of normal weight.[8] Women who are overweight or obese during their adult life have a higher risk of cerebral atrophy, which may contribute to cognitive decline, according to a Swedish study with 24-year follow up.[9] (See Medscape Medical News story.) The authors warn that "[i]f overweight and obesity contribute not only to diseases of middle age but also to degenerative diseases of late life, the health ramifications of excess body fat will stress healthcare systems for many years to come."

This year we also learned more about the effects of obesity on pregnancy and childbirth. Obesity has been associated with an increased risk of first-trimester and recurrent miscarriage.[10] What happens with an ongoing pregnancy has been investigated in 2 large population-based studies that focused on the risk of adverse obstetric outcomes. In the United States, Weiss and colleagues with the FASTER Research Consortium[11] published their findings from a prospective, multicenter database study showing that obesity and morbid obesity had a statistically significant association with gestational hypertension, preeclampsia, gestational diabetes, fetal birth weight > 4000 g and > 4500 g, and an increased rate of cesarean delivery. A Swedish study looked specifically at morbidly obese women (body mass index [BMI] > 40) and found an increased risk of preeclampsia, antepartum stillbirth, cesarean delivery, instrumental delivery, shoulder dystocia, meconium aspiration, fetal distress, early neonatal death, and large-for-gestational age (LGA) births.[12] Similar, although lesser, associations were found for women with BMI between 35.1 and 40.0. An increase in standard BMI category during pregnancy is associated with an increased risk of gestational diabetes, failed induction, laceration, and postpartum infection.[13] In addition, this study found overweight women had increased rates of preeclampsia and operative vaginal deliveries, and obese women had higher rates of chorioamnionitis, failed induction, and cesarean deliveries.

The rate of cesarean delivery is significantly higher for obese than for nonobese women.[11,12,13,14] Obese women may also have an increased risk for unsuccessful vaginal birth after cesarean delivery[15] and an increased risk for LGA deliveries.[11,12,16] Of note, women with diabetes have similar risk.

The trouble does not end with pregnancy and delivery, and in an interesting study published in 2004, Rasmussen and Kjolhede[17] considered the problem of the very low rate and short duration of breastfeeding among overweight and obese women. The authors state:

The unique and important finding from [our] study is that overweight/obese women had a lower prolactin response to suckling. This would be expected to compromise the ability of overweight/obese women to produce milk and, over time, could lead to premature cessation of lactation. These findings are important because, during our observation period (just before and after lactogenesis II, the time of onset of copious milk secretion), the prolactin response to suckling is more important for milk production than it is later in lactation. We have previously shown that a high proportion of the overweight and obese women in women in this population who give up on breastfeeding do so at this time. This finding thus provides evidence of a biological basis for this association, and additional study of it is likely to be informative.

These authors also give the following advice:

Pediatricians can help overweight/obese women to succeed at breastfeeding by targeting them for contact with a lactation consultant before discharge from the hospital to be sure that they have received optimal advice on breastfeeding techniques. In addition, early contact with the mother after discharge -- by calling her at home to offer her support and counseling for breastfeeding, by scheduling the first pediatric visit earlier than for other patients, or by enlisting the assistance of public health nurses for a home visit if this is possible -- would help overweight/obese women to continue to breastfeed.

This may be particularly important because, as shown in at least 1 study published in 2004, maternal obesity increases the risk of child obesity,[18] and an analysis of data from the CDC Pediatric Nutrition Surveillance System has shown that prolonged breastfeeding is associated with a reduced risk of overweight among non-Hispanic white children.[19]

The annual meeting of the Teratology Society this past summer focused on maternal obesity and diabetes and adverse pregnancy outcomes -- notably miscarriage, neural tube defects, congenital malformations, and neonatal death. According to a report on the meeting, scientists are worried that we are heading into a major crisis for women and their children.[20] A conference attendee, Thomas Moore, MD, of the University of California at San Diego, remarked:

"We used to think, at least the baby's out and it's safe... Well, that baby is not safe. We have set up this child for adverse health downstream -- certainly in childhood, and perhaps as an adult... [It is] a vicious cycle where an obese insulin-resistant woman has an obese fetus who becomes an obese neonate, who becomes an obese child, who is at greater risk to develop type 2 diabetes."

Obesity also has serious implications for aging women. Researchers from the Cancer Prevention Program, Fred Hutchinson Cancer Center, in Seattle, Washington, investigated the overall health burden of obesity in older adults, recruiting 73,003 adults aged 50 to 76, in the Vitamins and Lifestyle cohort study of western Washington State.[21] What they found was that of 41 health conditions (7 serious diseases, 2 conditions associated with cardiovascular disease risk, 23 medical conditions, and 11 health complaints), 37 (including diabetes, high blood pressure, knee replacement, gall bladder removal, pulmonary embolism, chronic fatigue, and insomnia) were associated with increased BMI in women. In addition, obesity increases risk of false-positive mammograms.[22] (See Medscape Medical News story.)

This past spring, Human Health Services Secretary Tommy G. Thompson announced a new national education campaign and a new research strategy at HHS's National Institutes of Health, "Strategic Plan for NIH Obesity Research," with a plan to spend $440.3 million in fiscal year 2005. Secretary Thompson remarked:

Americans need to understand that overweight and obesity are literally killing us...To know that poor eating habits and inactivity are on the verge of surpassing tobacco use as the leading cause of preventable death in America should motivate all Americans to take action to protect their health. We need to tackle America's weight issues as aggressively as we are addressing smoking and tobacco.

This was followed late summer with the American Cancer Society, American Diabetes Association, and the American Heart Association joint statement on preventing cancer, cardiovascular disease, and diabetes, all of which are associated with obesity, marking the beginning of a new collaboration between the 3 organizations.[23]

The goal of this joint venture is to stimulate substantial improvements in primary prevention and early detection through collaboration between key organizations, greater public awareness about healthy lifestyles, legislative action that results in more funding for and access to primary prevention programs and research, and reconsideration of the concept of the periodic medical checkup as an effective platform for prevention, early detection, and treatment. [23]

Yet, the question of motivating Americans to protect their health is a complex one. The link between food insecurity, hunger, and obesity, for example, is well known to those investigating the root causes of obesity (see footnote). It has become increasingly clear that, in many cases, socioeconomic factors underlie obesity and that those who are at greatest risk of becoming obese are the poor. I wrote about this in an editorial earlier this year, in part as a response to what seemed a loud call from members of the medical community and the government to adhere to healthy diet and vigorous exercise without an appreciably loud call from these members to address the social inequities in society that would enable its citizens to do so.

The opening page of the executive summary of the NIH Strategic Plan states that "overweight and obesity also disproportionately affect racial and ethnic minority populations, and those of lower socioeconomic status." The summary later notes that "because of the large racial/ethnic disparities in the incidence of obesity, a number of the efforts described in the Plan are directed at understanding the biologic and environmental factors contributing to such disparities and to addressing them in a culturally-sensitive manner." The NIH will focus on research toward preventing and treating obesity through lifestyle modification as well as pharmacologic, surgical, or other medical approaches. The document does mention obesity in relation to poverty and food insecurity: Research that is focused on the development and testing of a variety of new approaches for increasing physical activity, decreasing sedentary behaviors, and improving diet will -- as a short-term goal -- "explore the role of poverty, including food insecurity (limited access to safe, nutritious food) and lack of access to safe and convenient opportunities for physical activity, in the disproportionate prevalence of obesity in persons of low socioeconomic status." Is this sufficient?

A response to the American Cancer Society, the American Diabetes Association, and the American Heart Association joint statement on preventing cancer, cardiovascular disease, and diabetes by Clark and colleagues[24] makes a relevant point:

[T]hese diseases also share social causes that the statement does not address or acknowledge. The social determinants of these diseases are well recognized and documented in the research literature. These include social inequalities related to income differences and social exclusion, insecure and poor quality employment, lack of social support, poor literacy and lack of education opportunities, and addictions that result from all of the preceding.

Not surprisingly, people from socioeconomically deprived communities are more likely to be exposed to these social risk conditions, such that these risk conditions swamp the effects of lifestyle choices...

In effect, lifestyle choices may be more appropriately referred to as lifestyle chances for the proportion of the population with inadequate access to resources for initiating changes. Compounding this, people from socioeconomically deprived communities tend to benefit least from existing and new health services and treatments...

In addition to recommending steps to support willingness to change modifiable behavioral and system risk factors, governments, decision makers, and clinicians need to promote individual and community capacity to live healthier lives and support health policies and legislation that tackle both individual and societal or structural causes of the social conditions that give rise to these common diseases.

For more information online about hunger in the United States, see Center on Hunger, the Food Action and Resource Center, Foodfirst, America's Second Harvest, and the HungerWeb.


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