Psychobiology and behavioral strategies. Physical activity, sport participation, and suicidal behavior: U.S. high school students

PURPOSE

To evaluate the associations of physical activity and sports team participation with suicidal behavior among U.S. high school students.

METHODS

Data were from the 2003 Youth Risk Behavior Survey (N = 10,530 respondents). Exposure variables included physical activity (inactive, insufficient, moderately intensive, regular vigorously intensive, and frequent vigorously intensive) and sports team participation. Outcome variables were suicide ideation (seriously considering and/or planning suicide) and suicide attempts. Hierarchical logistic regressions were run, controlling for age, race, smoking, alcohol use, drug use, geographic region, unhealthy weight-control practices, and body mass index/weight perceptions.

RESULTS

Compared with inactive students or sports team nonparticipants, the odds of suicide ideation were lower among boys reporting frequent vigorous-intensity physical activity (adjusted odds ratio (AOR) = 0.48; 95% confidence interval (CI) = 0.29, 0.79) and sports team participation, respectively (AOR = 0.65; 95% CI = 0.48, 0.86). The odds of suicide attempts were also lower among frequently vigorously active boys (AOR = 0.44; 95% CI = 0.21, 0.96) and sports team participants (AOR = 0.61; 95% CI = 0.40, 0.93). The odds of suicide attempts were lower for regular vigorously active girls compared with inactive girls (AOR = 0.67; 95% CI = 0.45, 0.99) and sports team participants compared with nonparticipants (AOR = 0.73; 95% CI = 0.57, 0.94). Associations with one exposure variable generally weakened when adjustment was made for the other exposure variable, or for feeling sad and hopeless.

CONCLUSIONS

The association of physical activity and sports team participation with suicide ideation and suicide attempts varied by sex. Further research is needed to clarify these different associations.

Physical Activity-Related Injury and Body Mass Index Among US High School Students

Background:

Few studies have focused on the relationship between physical activity-related (PA) injury and overweight among youth.

Methods:

We analyzed data from the 2001 and 2003 Youth Risk Behavior Surveys (n = 28,815). Logistic regression was used to examine the independent effects of BMI and frequency of participation in vigorous activity, moderate activity, strengthening exercises, physical education (PE) classes, and team sports on the likelihood of PA injury.

Results:

Approximately 14% of females and 19% of males reported seeing a doctor or nurse during the previous 30 d for an injury that happened while exercising or playing sports. PA injury was associated with participation in team sports, strengthening exercises, and (among females) vigorous physical activity. Controlling for type and frequency of physical activity, injury was not associated with being overweight (BMI ≥ 95th percentile).

Conclusions:

Moderate physical activity and school PE classes may provide relatively low-risk alternatives for overweight youth who need to increase their physical activity.

Weight regain in U.S. adults who experienced substantial weight loss, 1999-2002

BACKGROUND

Relatively few studies have focused on who is at risk for weight regain after weight loss and how to prevent it. The objectives of this study were to determine the prevalence and predictors of weight regain in U.S. adults who had experienced substantial weight loss.

METHODS

Data were analyzed from the 1999-2002 National Health and Nutrition Examination Survey (NHANES). This study examined U.S. adults aged 20-84 years who were overweight or obese at their maximum weight (body mass index >/=25) and had experienced substantial weight loss (weighed 10% less than their maximum weight 1 year before they were surveyed) (n=1310).

RESULTS

Compared to their weight 1 year ago, 7.6% had continued to lose weight (>5%), 58.9% had maintained their weight (within 5%), and 33.5% had regained weight (>5%). Factors associated with weight regain (vs weight maintenance or loss) included Mexican American ethnicity (versus non-Hispanic white) (odds ratio [OR]=2.0; 95% confidence interval [CI]=1.3-3.1), losing a greater percentage of maximum weight (>/=20% vs 10% to <15%) (OR=2.8; 95% CI=2.0-4.1), having fewer years since reaching maximum weight (2-5 years vs >10 years) (OR=2.1; 95% CI=1.2-3.7), reporting greater daily screen time (>/=4 hours vs 0-1 hour) (OR=2.0; 95% CI=1.3-3.2), and attempting to control weight (OR=1.8; 95% CI=1.1-3.0). Finally, weight regain was higher in those who were sedentary (OR=1.8; 95% CI=1.0-3.0) or not meeting public health recommendations for physical activity (OR=2.0; 95% CI=1.2-3.5).

CONCLUSIONS

How to achieve the skills necessary for long-term maintenance of weight loss in the context of an obesogenic environment remains a challenge.

Sedentary behavior, recreational physical activity, and 7-year weight gain among postmenopausal U.S. women

OBJECTIVE

To assess the relationship among recreational physical activity (PA), non-occupational sedentary behavior, and 7-year weight gain among postmenopausal U.S. women 40 to 69 years old.

RESEARCH METHODS AND PROCEDURES

In 1992 and 1999, 18,583 healthy female participants from the Cancer Prevention Study II Nutrition Cohort completed questionnaires on anthropometric characteristics and lifestyle factors. The associations between recreational PA [in metabolic equivalent (MET) hours per week] and non-occupational sedentary behavior (in hours per day) at baseline and risk for 7-year weight gain (5 to 9 or >or =10 vs. +/-4 pounds) were assessed using multivariate logistic regression analysis.

RESULTS

Neither PA nor sedentary behavior was associated with a 5- to 9-pound weight gain. Among women who were not overweight at baseline (BMI <25.0), the odds of > or =10-pound weight gain were 12% lower (odds ratio, 0.88; 95% confidence interval, 0.77 to 0.99) for those in the highest category of recreational PA (> or =18 MET h/wk) compared with >0 to <4 MET h/wk; odds were 47% higher (odds ratio, 1.47; 95% confidence interval, 1.21 to 1.79) for non-overweight women who reported > or =6 h/d of non-occupational sedentary behavior compared with <3 h/d. Neither PA nor sedentary behavior were associated with risk of > or =10-pound weight gain weight among women who were overweight at baseline (BMI > or =25.0).

DISCUSSION

Both recreational PA and non-occupational sedentary behavior independently predicted risk of > or =10-pound weight gain among postmenopausal women who were not overweight at baseline. Public health messages to prevent weight gain among normal-weight postmenopausal women may need to focus on decreasing time spent in sedentary behaviors and increasing the amount of time spent on PA.

Use of Nonprescription Dietary Supplements for Weight Loss Is Common among Americans

OBJECTIVE

Dietary supplements are not recommended as part of a weight-loss program due to concerns about efficacy and safety. This study sought to assess prevalence and duration of nonprescription weight-loss supplement use, associated weight-control behaviors, discussion of use with a health care professional, and specific ingredient use.

PARTICIPANTS AND DESIGN

Adults aged > or =18 years (n=9,403) completed a cross-sectional population-based telephone survey of health behaviors from September 2002 through December 2002.

STATISTICAL ANALYSES PERFORMED

Both chi2 and t tests were conducted for categorical and mean comparisons and multiple variable logistic regression was used to determine significant predictors.

RESULTS

An estimated 15.2% of adults (women 20.6%, men 9.7%) had ever used a weight-loss supplement and 8.7% had past year use (women 11.3%, men 6.0%); highest use was among women aged 18 to 34 years (16.7%). In regression models, use was equally prevalent among race/ethnic groups and education levels. One in 10 (10.2%) of users reported > or =12 month use, with less frequent long-term use in women (7.7%) than men (15.0%), P=0.01. Almost one third (30.2%) of users discussed use during the past year; 73.8% used a supplement containing a stimulant including ephedra, caffeine, and/or bitter orange.

CONCLUSIONS

Use of supplements for losing weight seems to be common among many segments of the US adult population. Many adults are long-term users and most do not discuss this practice with their physician. Most of the weight-loss supplements taken contain stimulants. Qualified professionals should inquire about use of supplements for weight loss to facilitate discussion about the lack of efficacy data, possible adverse effects, as well as to dispel misinformation that may interfere with sound weight-management practices.

Reliability and Validity of a Brief Questionnaire to Assess Calcium Intake of Middle-School–Aged Children

OBJECTIVE

Evaluate the validity and reliability of a short (10-item) calcium food frequency questionnaire (FFQ) for use with middle-school-aged (11 to 14 years of age) children.

DESIGN

The calcium FFQ was completed twice, with 1 week between administrations. Three 24-hour dietary recalls were collected from each participant after the second administration of the calcium FFQ.

SUBJECTS/SETTING

Students in an ethnically diverse middle school in Minneapolis, MN (n=248).

MAIN OUTCOME MEASURES

Calcium intake estimates from the calcium FFQ and dietary recalls.

STATISTICAL ANALYSES

Correlations between calcium intake estimates from the first and second questionnaire administrations of the calcium FFQ were calculated and paired t tests were conducted to compare mean calcium intake estimates from each questionnaire administration. Mean intake estimates from the calcium FFQ and the dietary recalls were compared. Also, correlations between intake estimates from the calcium FFQ and the recalls were calculated.

RESULTS

Correlation between calcium intake estimates derived from the first and second administration of the calcium FFQ was 0.74. Mean calcium intake estimates from the calcium FFQ and the average of the three dietary recalls were 856 mg/day and 993 mg/day, respectively (P<0.001). The correlation between calcium intake estimates derived from the calcium FFQ and the average of the recalls was 0.43.

CONCLUSIONS

Reliability of the FFQ was found to be good while validity was weaker, with calcium intake from the calcium FFQ moderately associated with estimates from dietary recalls. Where a brief instrument for assessing calcium intake of middle-school-aged children is needed, the calcium FFQ evaluated in this study may be useful.

Predictors of nutrition counseling behaviors and attitudes in US medical students

BACKGROUND

Nutrition counseling by physicians can improve patients' dietary behaviors and is affected by physicians' nutrition practices and attitudes, such as the perceived relevance of nutrition counseling.

OBJECTIVE

The objective was to provide data on medical students' perceived relevance of nutrition counseling, reported frequency of nutrition counseling, and frequency of fruit and vegetable intakes.

DESIGN

Students (n = 2316) at 16 US medical schools were surveyed and tracked at freshmen orientation, at the time of orientation to wards, and in their senior year.

RESULTS

Freshmen students were more likely (72%) to find nutrition counseling highly relevant than were students at the time of ward orientation (61%) or during their senior year (46%; P for trend = 0.0003). Those intending to subspecialize had lower and declining perceptions of counseling relevance (P for trend = 0.0009), whereas the perceived relevance of counseling by primary care specialists remained high (P for trend = 0.5). Students were significantly more likely to find nutrition counseling highly relevant if they were female, consumed more fruit and vegetables, believed in primary prevention, had personal physicians who encouraged disease prevention, or intended to specialize in primary care. Only 19% of students believed that they had been extensively trained in nutrition counseling, and 17% of seniors reported that they frequently counseled their patients about nutrition. Students who consumed more fruit and vegetables, believed that they would be more credible if they ate a healthy diet, were not Asian or white, or intended to specialize in primary care counseled patients about nutrition more frequently. Medical students consumed an average of 3.0 fruit and vegetable servings/d, which declined over time.

CONCLUSIONS

The perceived relevance of nutrition counseling by US medical students declined throughout medical school, and students infrequently counseled their patients about nutrition. Interventions may be warranted to improve the professional nutritional practices of medical students.

Weight-control practices among U.S. adults, 2001-2002

BACKGROUND

Approximately $50 billion a year is spent by Americans on weight-loss products and services. Despite the high cost, few national studies have described specific weight-loss and weight-maintenance practices among U.S. adults. This analysis describes the use of specific practices by U.S. adults who tried to lose weight or tried only not to gain weight during the previous 12 months.

METHODS

Data were analyzed from the 2001-2002 National Health and Nutrition Examination Survey (NHANES) conducted on a nationally representative sample of the U.S. population. This study focused on adults aged 20 years or older who were both interviewed and examined (n =5027).

RESULTS

Fifty-one percent of U.S. adults tried to control their weight in the previous 12 months, including those who tried to lose weight (34% of men, 48% of women) and those who tried only not to gain weight (11% vs 10%, respectively). Among 2051 adults who tried to control their weight, the top four practices were the same: ate less food (65% among those who tried to lose weight, 52% among those who tried only not to gain weight); exercised (61% vs 46%, respectively); ate less fat (46% vs 42%); and switched to foods with lower calories (37% vs 36%). Less than one fourth combined caloric restriction with the higher levels of physical activity (300 or more minutes per week) recommended in the 2005 dietary guidelines by the U.S. Department of Health and Human Services and U.S. Department of Agriculture.

CONCLUSIONS

Although weight control is a common concern, most people who try do not use recommended combinations of caloric restriction and adequate levels of physical activity.

Secular trends in desired weight of adults

CONTEXT

The prevalence of overweight and obese adults in the United States is at record levels.

OBJECTIVE

The primary purpose is to describe secular trends in desired weight among adults from 1994 to 2003, and secondarily, to examine the hypothetical impact of achieving desired weight on obesity prevalence.

DESIGN

Data were from the Behavioral Risk Factor Surveillance System (1994, 1996, 1998, 2000, 2003), a random-digit-dialed telephone survey.

SETTING

Sample included respondents from 47 states and the District of Columbia.

PARTICIPANTS

Non-institutionalized adults aged 18 years or older were included (N=703 286).

MAIN OUTCOME MEASURES

Primary outcome measures included reported weight and desired weight.

RESULTS

Means for desired weight increased 2.3 kg between 1994 and 2003, and reported weights increased 3.9 kg. The increased trend was observed across several subgroups for age, race/ethnicity and education. Within subgroups of weight status, the trend has remained relatively stable, particularly when examined in relation to the difference between reported and desired weight as a percentage of reported body weight. Generally, overweight men desired weights approximately 4.5% less than their reported weight, and obese men desired weights approximately 15% less than their reported weight for each corresponding year. For women, approximate values of desired weight were 12% less than reported weight for overweight women and 24% less for obese women. The prevalence of obesity would decrease to 4.4% if individuals weighed their desired weight.

CONCLUSIONS

Americans are shifting their desired weight upward, concomitantly with an increase in their reported body weight.

Competitive foods and beverages available for purchase in secondary schools--selected sites, United States, 2004

School Health Profiles is conducted biennially to assess characteristics of school health programs. State and local departments of education and health select either all public secondary schools within their jurisdictions or a systematic, equal-probability sample of public secondary schools to participate in School Health Profiles. At each school, the principal and lead health education teacher were sent questionnaires to be self-administered and returned to the state or local agency conducting the survey. In 2004, a total of 27 states and 11 large urban school districts obtained weighted data from their survey of principals. The findings in this report indicate that the majority of secondary schools in 27 states and 11 large urban school districts allow students to purchase snack foods or beverages from vending machines or at the school store, canteen, or snack bar. The types of competitive foods and beverages available for purchase varied across states and large urban school districts. Overall, fruits or vegetables were less likely to be available for purchase than the other types of foods or beverages. Bottled water and soft drinks, sports drinks, or fruit drinks that are not 100% juice were most likely to be available for purchase.

Feasibility of using accelerometers to measure physical activity in young adolescents

PURPOSE

Accelerometers may provide valid measures of physical activity, but the feasibility of using accelerometers with large groups of children is unknown. We assessed feasibility in the Eating and Activity Survey Trial (Project EAST), a study designed to develop valid tools to assess eating and physical activity patterns among middle school children.

METHODS

Two hundred eighty-two Project EAST participants in grades 6-8 wore an accelerometer (Manufacturing Technologies, Inc., Fort Walton Beach, FL) for seven consecutive days. Multiple strategies were employed to encourage compliance and return of the accelerometer: 1) staff demonstrated how to wear the device properly; 2) students were given written and verbal instructions; 3) staff visited the students twice during 7 d to remind them to wear the devices and return them on time; and 4) movie tickets were given to students who returned the accelerometers on time.

RESULTS

Data from 27 accelerometers were lost as a result of mechanical and nontechnical problems, resulting in unusable data for 8.5% of students. Days of data for the remaining 255 students were considered incomplete if the accelerometer registered less than three consecutive waking hours of zero counts. The percentage of students with complete accelerometer data for 3-7 d of data were > or = 3 d, 92%; > or = 4 d, 86%; > or = 5 d, 75%; > or = 6 d, 67%; and 7 d, 50%. Twenty-eight students (10%) returned their accelerometers late. Overweight children were significantly more likely to have 7 d of complete data than nonoverweight children.

CONCLUSION

Our findings suggest that accelerometers are acceptable to most students. However, researchers working with middle school students should carefully monitor compliance to ensure that devices are worn properly and regularly.

Geographic variation in the prevalence of obesity, diabetes, and obesity-related behaviors

OBJECTIVE

To examine the variation in the prevalences of obesity and type 2 diabetes in weight loss counseling by health providers and in other potential obesity-related determinants in 100 metropolitan statistical areas in the United States.

RESEARCH METHODS AND PROCEDURES

We performed a cross-sectional study using data from the 2000 Behavioral Risk Factor Surveillance System, the largest telephone survey of health behaviors in the United States, of age-adjusted prevalence of obesity, type 2 diabetes, intake of >or=five servings of fruits and vegetables per day, participation in 150 minutes of leisure-time physical activity per week, receipt of weight management advice, and reports of trying to lose or maintain weight among men and women more than 18 years old.

RESULTS

The age-adjusted prevalence of obesity ranged from 13.1% to 30.0% and that of type 2 diabetes from 3.3% to 9.2%. Among participants who had visited a physician for a routine checkup in the previous 12 months, 13.1% to 27.1% of all participants recalled receiving advice from a health professional about their weight, and 11.7% to 34.6% of overweight or obese participants recalled receiving advice to maintain or lose weight.

DISCUSSION

Significant differences in the prevalence of obesity and self-reported type 2 diabetes and in medical practice patterns regarding weight management advice exist among metropolitan statistical areas. These results suggest important opportunities to investigate reasons for these variations that could potentially be used to mitigate the current epidemic of obesity and to identify areas where obesity and diabetes prevention efforts may need to be targeted.

Associations of Body Mass Index and Perceived Weight With Suicide Ideation and Suicide Attempts Among US High School Students

BACKGROUND

Previous research with adolescents has shown associations of body weight and perceptions of body size with suicide ideation and suicide attempts, but it is unclear whether these associations are direct or whether a mediating effect exists.

OBJECTIVES

To determine if body mass index and perceived weight are associated significantly with suicide ideation and suicide attempts, controlling for weight control practices, and if perceived weight mediates the associations of body mass index with suicide ideation and suicide attempts.

DESIGN, SETTING, AND PARTICIPANTS

Data were analyzed from the 2001 Youth Risk Behavior Survey, a school-based survey administered to a nationally representative sample of students in grades 9 through 12 (N = 13 601).

MAIN OUTCOME MEASURE

Self-reported past-year suicide ideation and suicide attempts, compared by perceived weight and body mass index category, calculated from self-reported height and weight.

RESULTS

Body mass index category was associated significantly with suicide ideation (among all students) and suicide attempts (among white and Hispanic students) without perceived weight in the model but not with perceived weight added to the model. In contrast with those who perceive themselves as about the right weight, students who perceived themselves as very underweight (odds ratio [OR], 2.29 [95% confidence interval (CI), 1.46-3.59]), slightly underweight (OR, 1.36 [95% CI, 1.03-1.79]), slightly overweight (OR, 1.33 [95% CI, 1.12-1.58]), and very overweight (OR, 2.50 [95% CI, 1.73-3.60]) had greater adjusted odds of suicide ideation. Among white students, perceiving oneself as very underweight (OR, 3.04 [95% CI, 1.40-6.58]) or very overweight (OR, 2.74 [95% CI, 1.21-6.23]) was associated with greater odds of suicide attempts. Perceiving oneself as very underweight was associated with greater odds for suicide attempts among black (OR, 2.86 [95% CI, 1.10-7.45]) and Hispanic (OR, 3.40 [95% CI, 1.54-7.51]) students.

CONCLUSIONS

How adolescents perceive their body weight may be more important than their actual weight in terms of increased likelihood of suicidal behavior. Regardless of body mass index, extreme perceptions of weight appear to be significant risk factors for suicidal behavior; important racial/ethnic differences exist.

Weight management goals and use of exercise for weight control among U.S. high school students, 1991-2001

PURPOSE

The purpose of this study was to examine trends in weight management goals and the use of exercise for weight control among U.S. high school students.

METHODS

As part of the Youth Risk Behavior Surveillance System, 6 national school-based surveys were conducted between 1991 and 2001. Each survey used a three-stage cross-sectional sample of students in grades 9-12. African-American and Hispanic students were oversampled. Logistic regression models were used to test for trends among gender and race/ethnic subgroups, controlling demographic changes over time.

RESULTS

From 1991 to 2001, the percentage of female students trying to lose weight (61.7%-62.3%) or stay the same weight (15.4%-16.0%) did not change significantly. Among male students, trying to lose weight (22.7%-28.8%) and trying to stay the same weight (17.8%-21.5%) both increased significantly, while trying to gain weight decreased significantly (32.7%-26.3%). Among female and male students who were trying to lose weight or stay the same weight, the use of exercise for weight control increased significantly. Among students who reported using exercise for weight control, participation in vigorous physical activity > or = 3 days per week increased among African-American female students, and participation in strengthening exercises > or = 3 days per week increased among male students.

CONCLUSIONS

These findings suggest increased interest in weight control among male adolescents, and increased use of exercise for weight control among female and male adolescents.

Physical Activity Profiles of U.S. Adults Trying to Lose Weight: NHIS 1998

PURPOSE

Physical activity is an integral part of weight control programs, but recommended amounts vary. The objectives of this study were to describe the prevalence and characteristics of those who reported using exercise as a weight loss strategy (N=14,716), and to determine the prevalence of meeting various institutionally recommended levels of physical activity (N=8538) among that population.

METHODS

Data were obtained from the 1998 National Health Interview Survey, a face-to-face nationally representative household interview. Questions on leisure-time physical activity were analyzed using SUDAAN.

RESULTS

Among those who reported trying to lose weight, 55% reported using exercise as a weight loss strategy alone, and of those, 58% reported eating fewer calories. The prevalence of using exercise as a weight loss strategy was directly associated with education and inversely associated with age and body mass index. Among those who reported using exercise as a weight loss strategy, 57% met the minimal 1998 National Institutes of Health recommendation of >or=150 min.wk; 46% met the lower end of the 2001 American College of Sports Medicine recommendation of 200 min.wk; and 30% met the upper end for 300 min.wk. Only 19% met the 2002 Institute of Medicine recommendation of 420 min.wk.

CONCLUSIONS

Despite the importance of physical activity in a weight loss program, only about half of the persons trying to lose weight reported using exercise. Even among those, only slightly more than half met the minimal recommendations for physical activity. Efforts are needed to aid those trying to lose weight to incorporate appropriate levels of physical activity into their weight loss strategy.

Public health and clinical recommendations for physical activity and physical fitness: special focus on overweight youth

Numerous physical activity and physical fitness recommendations exist for youth. To date, however, no investigator has systematically reviewed these public health and clinical guidelines to determine whether the recommendations address overweight youth. This review examines youth-oriented physical activity and physical fitness recommendations for both the public health community and the clinical community, and assesses how overweight youth are specifically targeted by each of these two groups. Our review determined the extent to which the recommendations assessed four components of physical activity (i.e. frequency, intensity, duration and type) and four components of physical fitness (i.e. cardiorespiratory capacity, strength, flexibility and body composition). We further reviewed clinical recommendations to determine how they included two facets of the physician-patient encounter: assessment and counselling. After identifying all current physical activity and physical fitness recommendations for youth, we evaluated whether public health (n = 13) and clinical recommendations (n = 12) addressed physical activity and physical fitness for overweight youth. Findings revealed inconsistent, yet explicit, recommendations for the public health community where most organisations (12 of 13, 92%) included > or =3 physical activity components. In addition, organisations encouraged volumes of daily moderate- to vigorous-intensity physical activity for youth ranging from 30-60 or more minutes. Recommendations for the clinical community generally did not provide explicit physical activity and fitness recommendations to advise physicians on the assessment and counselling of patients and their families. Overweight youth were addressed within some recommendations (6 of 12, 50%) for the clinical community, but within few recommendations (2 of 13, 15%) for the public health community. To best inform public health and clinical communities, organisations developing future recommendations should include information fully documenting the decision-making processes used to develop the recommendations. In cases where mutual goals exist, public health and clinical communities should consider collaborating across agencies to develop joint recommendations.

Personal and clinical exercise-related attitudes and behaviors of freshmen U.S. medical students

To determine personal and clinical exercise-related attitudes and behaviors of freshmen U.S. medical students, we surveyed 1,906 entering freshman medical students (response rate = 87%; average age = 24 years) in 17 U.S. medical schools. Students reported a median of 45 min/day of exercise, 80 min/week each of mild and moderate exercise, and 100 min/week of strenuous exercise. Nearly all students (97.6%) engaged in some moderate or vigorous exercise in a typical week. Sixty-four percent complied with U.S. Department of Health and Human Services exercise recommendations. Most freshmen (79%) believed it would be highly relevant to their future practices to counsel patients about exercise; predictors included intention to provide primary care, excellent health, prevention emphasis by their personal physician, and performing more strenuous exercise.

Attempting to lose weight: specific practices among U.S. adults

BACKGROUND

Americans spend over $33 billion annually on weight-loss products and services. Although weight-control methods are of considerable public health interest, few national data on weight-loss practices are available. This paper examines the prevalence of specific weight-loss practices among U.S. adults trying to lose weight.

METHODS

Data from the 1998 National Health Interview Survey, which was conducted through face-to-face interviews of a nationally representative sample of U.S. adults (n =32,440), were analyzed in 2003.

RESULTS

Twenty-four percent of men and 38% of women were trying to lose weight. Attempting weight loss was less common among normal weight (body mass index [BMI]<25 kg/m(2)) people (6% men, 24% women) than overweight (BMI>/=25 to 30 kg/m(2)) people (28%, 49%) or obese (BMI>/=30 kg/m(2)) people (50%, 58%). Among those trying to lose weight, the most common strategies were eating fewer calories (58% men, 63% women); eating less fat (49%, 56%); and exercising more (54%, 52%). Less frequent strategies were skipping meals (11% men, 9% women); eating food supplements (5%, 6%); joining a weight-loss program (3%, 5%); taking diet pills (2%, 3%); taking water pills or diuretics (1%, 2%); or fasting for >/=24 hours (0.6%, 0.7%). Only one third of all those trying to lose weight reported eating fewer calories and exercising more.

CONCLUSIONS

Increased efforts are needed among all those trying to lose weight to promote effective strategies for weight loss, including the use of calorie reduction and increased physical activity.

The epidemiology of recent involuntary weight loss in the United States population

BACKGROUND

Although recent involuntary weight loss (RIWL) has been associated with mortality, no national studies described the prevalence among the general population, characteristics and long-term outcomes of people with RIWL.

METHODS

The authors analyzed data from the NHANES II Mortality Study of 5838 individuals 50-74.9 years old who between 1976-1980 underwent a physical examination that included height and weight measurements, biochemical tests and responded to questions about involuntary weight loss within the past six months. Vital status was determined through 1992. Logistic regression was used to examine characteristics associated with RIWL and Cox proportional hazard modeling was used to measure associations between RIWL and mortality.

RESULTS

13.3% of the population reported RIWL with 6.9% reporting > or = 5% RIWL. Obese individuals were at significantly higher risk of RIWL of > or = 5% compared to those with BMI 19-24.9 (OR=1.57. 95% CI: 1.13, 2.18). Other significant risk factors for RIWL included; poor self-reported health, cancer, high white blood cell count, low albumin and low hemoglobin levels, age and current smoking status. RIWL of > or = 5% was significantly associated with mortality (RR=1.24, 95% CI: 1.01, 1.53).

CONCLUSION

In summary, RIWL is fairly common among community-dwelling older adults, occurs disproportionately among obese individuals, is associated with characteristics of poor health and independently associated with mortality. These results indicate that RIWL needs to be considered an adverse health indicator even among obese individuals and despite the absence of several clinical indicators of disease.

Walking trends among U.S. adults: the Behavioral Risk Factor Surveillance System, 1987-2000

OBJECTIVE

To examine trends in walking among adults in 31 states.

METHODS

Trends by sociodemographic strata were analyzed from respondents who participated in the Behavioral Risk Factor Surveillance System (BRFSS).

RESULTS

The prevalence of walking among men increased 3.8% (95% confidence interval [CI]=2.4-5.2), from 26.2% (95% CI=25.1-25.3) in 1987 to 30.1% (95% CI=29.4-30.8) in 2000. In women, walking increased 6.6% (95% CI=5.4-7.8), from 40.4% (95% CI=-39.4-41.1) to 46.9% (95% CI=46.2-47.6) during the same time period. However, the prevalence of walking three times a week for 30 minutes duration remained constant across all years. The largest increases occurred in minority subpopulations: 8.7% (95% CI=3.2-14.2) in Hispanic women, 8.5% (95% CI=4.4-12.6) non-Hispanic black women, and 7.0% (95% CI=2.3-11.7) in non-Hispanic black men. Walking was the most frequently reported activity among adults who met the national recommendations for regular physical activity (defined as five or more times a week for > or =30 minutes per session).

CONCLUSIONS

Given the acceptability of walking across all sociodemographic subgroups, efforts to increase the frequency of walking could markedly increase the percentage of U.S. adults who engage in regular physical activity, a national priority identified in the Healthy People 2010 objectives for the nation.

Maternal perceptions of weight status of children

OBJECTIVE

We quantified maternal misclassification of child weight status and examined determinants associated with maternal perceptions of child weight status.

METHODS

Data from the Third National Health and Nutrition Examination Survey (1988-1994) were used. The sample included 5500 children (aged 2-11 years) with maternal interview data. Maternal perceptions of children's weight status were compared with measured weights and statures from which body mass index (BMI; weight/stature2; kg/m2) percentiles and z scores were determined. Frequency analyses determined the percentages of mothers considering their child to be "overweight," "underweight," or "about the right weight." Multivariable logistic regression analyses determined predictors of maternal misclassification of overweight children (> or =95th BMI-for-age percentile) and those at risk for overweight (> or =85th to <95th BMI-for-age percentile).

RESULTS

Nearly one third (32.1%) of mothers reported their overweight child as "about the right weight." Younger children and those with lower BMI-for-age z scores had significantly greater odds of maternal underclassification of child overweight status. For children at risk for overweight, 14.0% of mothers reported sons to be "overweight," whereas 29.0% considered daughters to be "overweight." Odds of maternal misclassification of at-risk children as "overweight" were significantly greater for daughters, older children, children with higher BMI-for-age z scores, and children whose mothers had a lower BMI. Race/ethnicity was not a significant predictor in either model.

CONCLUSIONS

Nearly one third of mothers misclassify overweight children as being lower than their measured weight status. Mothers are more likely to identify daughters who are at risk of overweight as being "overweight" than they are sons.

Reliability and validity of self-reported height and weight among high school students

PURPOSE

To assess the reliability and validity of self-reported height and weight, and variables calculated from these values, in a diverse sample of adolescents.

METHODS

A convenience sample of students (n = 4619) in grades 9 through 12 reported their height and weight on two questionnaires administered approximately 2 weeks apart. Using a standard protocol, a subsample of these students (n = 2032) also were weighed and had their height measured following completion of the first questionnaire.

RESULTS

Self-reported heights at Time 1 and Time 2 were highly correlated, and the mean difference between height at Time 1 and Time 2 was small. Results were similar for self-reported weight at Time 1 and Time 2 and body mass index (BMI) calculated from these values. Although self-reported values of height, weight, and BMI were highly correlated with their measured values, on average, students overreported their height by 2.7 inches and underreported their weight by 3.5 pounds. Resulting BMI values were an average of 2.6 kg/m(2) lower when based on self-reported vs. measured values. The percentages of students classified as "overweight" or "at risk for overweight" were therefore lower when based on self-reported rather than on measured values. White students were more likely than those in other race/ethnic groups to overreport their height, and the tendency to overreport height increased by grade. Female students were more likely than male students to underreport their weight.

CONCLUSIONS

Self-reported height, weight, and BMI calculated from these values were highly reliable but were discrepant from measured height, weight, and BMIs calculated from measured values. BMIs based on self-reported height and weight values therefore underestimate the prevalence of overweight in adolescent populations.

Weight-loss practices and asthma: findings from the behavioral risk factor surveillance system

OBJECTIVE

To describe weight-control practices and receipt of weight-loss advice among obese people with asthma.

RESEARCH METHODS AND PROCEDURES

We analyzed data from the 2000 Behavioral Risk Factor Surveillance System.

RESULTS

Among 13953 participants with current asthma, 27.3% had a body mass index of >or=30 kg/m2. Overall, 48.1% of participants with asthma reported trying to lose weight (64.1% among overweight or obese participants and 72.9% among obese participants). Among participants with asthma who were trying to lose or maintain weight, 74.7% reported trying to reduce their energy and/or fat intake, and 57.8% reported using physical activity. Approximately 29.7% were using the recommended combination of energy and/or fat intake reduction and physical activity of >or=150 min/wk. During the 12 months before the interview, 16.2% of overweight and 44.9% of obese participants with asthma reported receiving advice to lose weight. Among obese participants receiving weight-loss advice, 82.9% reported trying to lose weight compared to 63.8% of participants who did not receive such advice.

DISCUSSION

Health professionals can play an important role in educating their patients with asthma about the importance of weight control and assisting their overweight and obese patients in setting appropriate weight goals and helping them achieve those goals.

Television viewing and its associations with overweight, sedentary lifestyle, and insufficient consumption of fruits and vegetables among US high school students: differences by race, ethnicity, and gender

Television (TV) viewing has been associated with overweight, decreased physical activity, and unhealthy dietary behavior among children and adolescents, and may represent a modifiable cause of childhood obesity. This study examined race, ethnic, and gender-specific differences in these associations among high school students in the United States. The study analyzed data from the 1999 national Youth Risk Behavior Survey, a representative sample (N = 15,349) of US high school students. Logistic regression tested for significant associations. TV viewing on an average school day exceeded 2 hours/day among 43% of students; it was greater among Black (74%) and Hispanic (52%) than White (34%) students. Overall, 11% of students were overweight, 31% of students were sedentary (i.e., did not participate in moderate or vigorous physical activity at recommended levels), and 76% ate less than five servings/day of fruits and vegetables. Watching TV more than 2 hours/day was associated with being overweight, being sedentary, and eating insufficient fruits and vegetables among White females, and with being overweight among Hispanic females. No significant associations were found among Black females. TV viewing was associated with being overweight and eating insufficient fruits and vegetables among White males. No significant associations were found among Hispanic males. Among Black males, TV viewing was associated with greater participation in physical activity. These findings suggest the presence of cultural factors to consider when developing interventions to promote physical activity, healthy eating, and healthy weight through reduced TV viewing among adolescents.

Trends and correlates of class 3 obesity in the United States from 1990 through 2000

CONTEXT

Although the prevalence of obesity has markedly increased among US adults, health risks vary according to the severity of obesity. Persons with class 3 obesity (body mass index [BMI] > or = 40) are at greatest risk, but there is little information about this subgroup.

OBJECTIVE

To examine correlates of class 3 obesity and secular trends.

DESIGN, SETTING, AND PARTICIPANTS

Adults (aged > or = 18 years) in the United States who participated in the Behavioral Risk Factor Surveillance System telephone survey between 1990 (75,600 persons) and 2000 (164,250 persons).

MAIN OUTCOME MEASURE

Body mass index calculated from self-reported weight and height.

RESULTS

The prevalence of class 3 obesity increased from 0.78% (1990) to 2.2% (2000). In 2000, class 3 obesity was highest among black women (6.0%), persons who had not completed high school (3.4%), and persons who are short. During the 11-year period, the median BMI level increased by 1.2 units and the 95th percentile increased by 3.2 units.

CONCLUSION

The prevalence of class 3 obesity is increasing rapidly among adults. Because these extreme BMI levels are associated with the most severe health complications, the incidence of various diseases will increase substantially in the future.

Relationship of satisfaction with body size and trying to lose weight in a national survey of overweight and obese women aged 40 and older, United States

BACKGROUND

Despite the potential benefits of weight loss, the factors associated with weight loss behavior are only beginning to be identified. We examined the association between sociodemographic factors, perceived health, satisfaction with body size, and trying to lose weight.

METHODS

Data were obtained from the 1996-1997 U.S. Women's Determinants Study. We included over 1,700 overweight and obese women aged 40 and older from the following four racial/ethnic groups: Hispanic, black, American Indian/Alaskan Native, and non-Hispanic white.

RESULTS

About half of the women reported that they were satisfied or very satisfied with their body size. Satisfaction was associated with lower body mass index (BMI), greater age, lower educational level, and better self-rated health. Compared with non-Hispanic white women, women in the other racial/ethnic groups expressed greater body satisfaction. About 65% of women reported that they were currently trying to lose weight. The strongest predictor of trying to lose weight was satisfaction with body size; women who were not satisfied were nine times more likely to report trying to lose weight than those who were very satisfied. Other significant predictors were BMI, race/ethnicity, and age.

CONCLUSIONS

Our findings should serve as the impetus for the inclusion of measures of body image in surveillance and intervention studies of weight loss and control.

Weight management goals and practices among U.S. high school students: associations with physical activity, diet, and smoking

PURPOSE

To examine associations of physical activity, fruit and vegetable consumption, and cigarette smoking with weight management goals and practices of U.S. high school students.

METHODS

Data were from the 1999 national Youth Risk Behavior Survey, a representative sample of U.S. high school students (n = 15,349). Adjusted odds ratios (OR) were calculated to describe associations, controlling for demographic characteristics.

RESULTS

Based on self-reported height and weight, 25% of students were either overweight (11%) or at risk for becoming overweight (14%). However, 43% of students were trying to lose weight and 19% of students were trying to maintain their current weight. Female students were less likely than male students to be overweight, but more likely to be trying to lose weight. Trying to lose weight was associated with vigorous physical activity (OR = 1.5), strengthening exercises (OR = 2.2), and cigarette smoking (OR = 1.4) among female students; and vigorous physical activity (OR = 1.6), strengthening exercises (OR = 1.8), and eating > or =5 servings/day of fruits and vegetables (OR = 1.5) among male students. Among students trying to lose weight or stay the same weight, only 62% of females and 41% of males combined exercise with a reduced fat and calorie diet, while 32% of females and 17% of males used unhealthy weight control methods (fasting, diet pills, vomiting, or laxatives).

CONCLUSIONS

Efforts to promote healthy weight management among adolescents are needed and should place greater emphasis on combining physical activity with a reduced fat and calorie diet, increasing fruit and vegetable consumption, and discouraging smoking and other unhealthy weight control practices.

Pediatrician counseling about preventive health topics: results from the Physicians' Practices Survey, 1998-1999

OBJECTIVE

Government agencies and national organizations recommend that physicians counsel their child and adolescent patients about preventive health topics. Using data from a national survey, we describe the counseling patterns of pediatricians in regard to 9 recommended preventive health topics.

METHODOLOGY

Between October 1998 and April 1999, information was collected from 907 of 1760 primary care pediatricians randomly selected from a nationally representative sample. Through either a telephone interview or a mail survey, pediatricians were asked how frequently in the past month they counseled about 9 preventive health topics during the well-care visits or routine check-ups of their patients. Pediatricians answered questions regarding their patients aged 2 to 5, 6 to 12, and 13 to 18 years.

RESULTS

Over 80% of the pediatricians counseled about 1 or more recommended preventive health topics during the well-care visits or routine check-ups of their patients. As compared with pediatricians who did not counsel about any topic, pediatricians who counseled were significantly more likely to be female and spend longer amounts of time with their patients during these visits. The frequency with which specific preventive health topics were discussed varied with the topic and the age of the patient.

CONCLUSION

Most pediatricians routinely counsel about some, but not all, recommended preventive health topics. An understanding of why pediatricians selectively counsel about specific topics is needed.

Achieving a healthy lifestyle among United States adults: a long way to go

OBJECTIVE

The United States population has been advised to engage in various healthy lifestyle factors known to be associated with reduced morbidity and mortality from various chronic conditions. These include not smoking, adequate fruit and vegetable intake, adequate physical activity, and normal body weight. Little is known about the prevalence of United States adults who engage in all four of these behaviors, however.

DESIGN

Cross-sectional analysis.

SETTING

The third National Health and Nutrition Examination Survey (1988-1994).

PARTICIPANTS

16,176 participants aged > or = 21 years.

MAIN OUTCOME MEASURES

Percentage of participants engaging in four healthy lifestyle factors.

RESULTS

Overall, 6.8% of the US population engaged in all four healthy lifestyle factors. Women were more likely than men (P = .001), and Whites and participants of "other race or ethnicity" were more likely than African Americans and Mexican Americans to engage in all four healthy lifestyle factors. A significant positive educational gradient was also evident (P for linear trend <.001). The highest percentages of participants engaging in all four lifestyle factors occurred among men (15.8%) and women (18.4%) of "other" race who had at least 13 years of education. The lowest percentages were observed for White men (1.1%) and African-American women (0.9%) with little education.

CONCLUSIONS

The small proportion of US adults engaging in four healthy lifestyle factors demonstrates the enormity of the task that awaits the public health community in persuading Americans to adopt a multidimensional healthy lifestyle.

Cigarette smoking and diabetes mellitus: evidence of a positive association from a large prospective cohort study

OBJECTIVE

Only a few prospective studies have examined the relationship between the frequency of cigarette smoking and the incidence of diabetes mellitus. The purpose of this study was to determine whether greater frequency of cigarette smoking accelerated the development of diabetes mellitus, and whether quitting reversed the effect.

METHODS

Data were collected in the Cancer Prevention Study I, a prospective cohort study conducted from 1959 through 1972 by the American Cancer Society where volunteers recruited more than one million acquaintances in 25 US states. From these over one million original participants, 275,190 men and 434,637 women aged > or = 30 years were selected for the primary analysis using predetermined criteria.

RESULTS

As smoking increased, the rate of diabetes increased for both men and women. Among those who smoked > or = 2 packs per day at baseline, men had a 45% higher diabetes rate than men who had never smoked; the comparable increase for women was 74%. Quitting smoking reduced the rate of diabetes to that of non-smokers after 5 years in women and after 10 years in men.

CONCLUSIONS

A dose-response relationship seems likely between smoking and incidence of diabetes. Smokers who quit may derive substantial benefit from doing so. Confirmation of these observations is needed through additional epidemiological and biological research.

C-reactive protein and body mass index in children: findings from the Third National Health and Nutrition Examination Survey, 1988-1994

OBJECTIVES

To examine the relationship between C-reactive protein (CRP) concentration and body mass index (BMI) in children.

STUDY DESIGN

With the use of data from 5305 children aged 6 to 18 years in the Third National Health and Nutrition Examination Survey (1988 to 1994), a cross-sectional health survey, we examined whether CRP concentrations were elevated among overweight children.

RESULTS

Among children whose BMI was below the age- and sex-specific 15th percentile, 6.6% of boys and 10.7% of girls had an elevated CRP concentration (>2.1 mg/L) compared with 24.2% of boys and 31.9% of girls whose BMI was > or =95th percentile. After adjustment was done for age, sex, race or ethnicity, poverty income ratio, high-density lipoprotein cholesterol concentration, white blood cell count, and history of chronic bronchitis, the adjusted odds of having an elevated CRP concentration were 2.20 (95% CI 1.30, 3.75) for children with a BMI of 85th to <95th percentile and 4.92 (95% CI 3.39, 7.15) for children with a BMI of > or =95th percentile compared with children who had a BMI of 15th to <85th percentile. The associations did not differ significantly by age, sex, or race or ethnicity.

CONCLUSIONS

In a large representative sample of US children, CRP concentration was significantly elevated among children with a BMI > or=85th percentile, thus confirming previous findings of this association in children and extending previous research in adults to children. Excess body weight may be associated with a state of chronic low-grade inflammation in children.

Is caffeine associated with bone mineral density in young adult women?

BACKGROUND

By increasing the urinary excretion of calcium, caffeine consumption may reduce bone mineral density (BMD) and subsequently increase the risk for osteoporotic fracture. Although negative associations between caffeine consumption and BMD have been reported for postmenopausal women, in particular for those who consume low amounts of dietary calcium, the relation between caffeine and BMD in younger women is unclear. Therefore, we evaluated the association between caffeine consumption and BMD in a cross-sectional study of 177 healthy white women, age 19-26 years, who attended a Midwestern university.

METHODS

Average caffeine intake (milligrams per day) was calculated from self-reports of the consumption of coffee, decaffeinated coffee, tea, colas, chocolate products, and select medications during the previous 12 months (mean caffeine intake = 99. 9 mg/day). BMD (grams per square centimeter) at the femoral neck and the lumbar spine was measured by dual-energy X-ray absorptiometry.

RESULTS

After adjusting in linear regression models for potential confounders, including height, body mass index, age at menarche, calcium intake, protein consumption, alcohol consumption, and tobacco use, caffeine consumption was not a significant predictor of BMD. For every 100 mg of caffeine consumed, femoral neck BMD decreased 0.0069 g/cm(2) (95% confidence in terval [CI] = -0.0215, 0. 0076) and lumbar spine BMD decreased 0.0119 g/cm(2) (95% CI = -0. 0271, 0.0033). No single source of caffeine was significantly associated with a decrease in BMD. Furthermore, the association between caffeine consumption and BMD at either site did not differ significantly between those who consumed low levels of calcium (< or =836 mg/day) and those who consumed high levels of calcium (>836 mg/day).

CONCLUSIONS

Caffeine intake in the range consumed by young adult women is not an important risk factor for low BMD.

Social relationships and cardiovascular disease risk factors: findings from the third national health and nutrition examination survey

Objective. Our aim was to study the associations between social relationships and several health behaviors in a national sample of the U.S. population. Methods. Using data from National Health and Nutrition Examination Survey III, which was conducted from 1988 to 1994, we examined the associations between the frequencies of organizational and individual relationships (derived from factor analysis) and cigarette smoking, not having had a blood pressure check during the preceding 12 months, not having had a cholesterol check, not engaging in physical activity, and eating fruits and vegetables fewer than five times per day among men and women aged 18 years and older. Results. After adjusting for age, sex, race, educational attainment, marital status, and employment status, increases in organizational relationships were associated with decreases in all five behaviors: significant inverse linear trends were noted only for smoking and physical activity. For individual relationships, significant inverse linear trends were noted for not having a blood pressure check within the previous 12 months, not having had a cholesterol check, and inadequate fruit and vegetable consumption. For physical inactivity, the shape of the relationship approximated a threshold response. For smoking, a significant positive linear trend was present. Conclusions. These results support findings from previous studies and indicate that social relationships have a beneficial effect on several behaviors that directly or indirectly affect the risk of cardiovascular disease.

Physical activity, food choice, and weight management goals and practices among US college students

INTRODUCTION

Physical activity and a healthy diet have been recommended to help reverse the increasing prevalence of overweight among adolescents and adults in the United States.

METHODS

Data is from the 1995 National College Health Risk Behavior Survey. A representative sample of US undergraduate college students (n = 4609) were analyzed to examine associations of physical activity and food choice with weight management goals and practices.

RESULTS

Based on self-reported height and weight, 35% of students were overweight or obese (body mass index > or = 25.0). Nearly half (46%) of all students reported they were trying to lose weight. Female students were less likely than male students to be overweight, but more likely to be trying to lose weight. Among female and male students, using logistic regression to control for demographics, trying to lose weight was associated with participation in vigorous physical activity and strengthening exercises, and consumption of < or = 2 servings/ day of high-fat foods. Female and male students who reported using exercise to lose weight or to keep from gaining weight were more likely than those who did not to participate in vigorous, strengthening, and moderate physical activity, and were more likely to eat > or = 5 servings/day of fruits and vegetables and < or = 2 servings/day of high-fat foods. Among students who were trying to lose weight, only 54% of females and 41% of males used both exercise and diet for weight control.

CONCLUSION

Colleges should implement programs to increase student awareness of healthy weight management methods and the importance of physical activity combined with a healthy diet.

Are health care professionals advising obese patients to lose weight?

CONTEXT

Implementation of the National Institutes of Health's 1998 guidelines, which recommended that health care professionals advise obese patients to lose weight, required baseline data for evaluation.

OBJECTIVES

To describe the proportion and characteristics of obese persons advised to lose weight by their health care professional during the previous 12 months and to determine whether the advice was associated with reported attempts to lose weight.

DESIGN

The Behavioral Risk Factor Surveillance System, a random-digit telephone survey conducted in 1996 by state health departments.

SETTING

Population-based sample from 50 states and the District of Columbia.

PARTICIPANTS

A total of 12835 adults, 18 years and older, classified as obese (body mass index > or =30 kg/m2), who had visited their physician for a routine checkup during the previous 12 months.

MAIN OUTCOME MEASURES

Reported advice from a health care professional to lose weight, and reported attempts to lose weight.

RESULTS

Forty-two percent of participants reported that their health care professional advised them to lose weight. Using multivariate logistic regression analysis, we found that the persons who were more likely to receive advice were female, middle aged, had higher levels of education, lived in the northeast, reported poorer perceived health, were more obese, and had diabetes mellitus. Persons who reported receiving advice to lose weight were significantly more likely to report trying to lose weight than those who did not (OR, 2.79; 95% CI, 2.53-3.08).

CONCLUSIONS

Less than half of obese adults report being advised to lose weight by health care professionals. Barriers to counseling need to be identified and addressed.

Prevalence of attempting weight loss and strategies for controlling weight

CONTEXT

Overweight and obesity are increasing in the United States. Changes in diet and physical activity are important for weight control.

OBJECTIVES

To examine the prevalence of attempting to lose or to maintain weight and to describe weight control strategies among US adults.

DESIGN

The Behavioral Risk Factor Surveillance System, a random-digit telephone survey conducted in 1996 by state health departments. Setting The 49 states (and the District of Columbia) that participated in the survey.

PARTICIPANTS

Adults aged 18 years and older (N = 107 804).

MAIN OUTCOME MEASURES

Reported current weights and goal weights, prevalence of weight loss or maintenance attempts, and strategies used to control weight (eating fewer calories, eating less fat, or using physical activity) by population subgroup.

RESULTS

The prevalence of attempting to lose and maintain weight was 28.8% and 35.1 % among men and 43.6% and 34.4% among women, respectively. Among those attempting to lose weight, a common strategy was to consume less fat but not fewer calories (34.9% of men and 40.0% of women); only 21.5% of men and 19.4% of women reported using the recommended combination of eating fewer calories and engaging in at least 150 minutes of leisure-time physical activity per week. Among men trying to lose weight, the median weight was 90.4 kg with a goal weight of 81.4 kg. Among women, the median weight was 70.3 kg with a goal weight of 59.0 kg.

CONCLUSIONS

Weight loss and weight maintenance are common concerns for US men and women. Most persons trying to lose weight are not using the recommended combination of reducing calorie intake and engaging in leisure-time physical activity 150 minutes or more per week.

Menstrual history and bone density in young women

Adequate levels of reproductive and pituitary hormones are needed for the initiation and maintenance of regular menstrual cycles as well as for the achievement of peak bone mineral density (BMD). Therefore, in the absence of direct hormone measures, menstrual history may serve as a surrogate for the adequacy of hormonal functioning and be a marker for bone status in young women. In our cross-sectional study of white college women aged 19-26 years, we examined the association of six characteristics of menstrual history with bone density at the lumbar spine and the femoral neck. To characterize associations, we used multiple linear regression models that also accounted for the contribution of body mass index, dietary calcium intake, height, level of physical activity, smoking, and alcohol use. The associations between each of the six menstrual characteristics and BMD were stronger at the lumbar spine than at the femoral neck. Age at menarche explained the most variance at both the lumbar spine (partial r2 x 100 = 5.9%) and the femoral neck (partial r2 x 100 = 2.1%). For each year that menarche was delayed, bone density was lower by -0.023 g/cm2 (p = 0.0024) at the lumbar spine and -0.0129 g/cm2 (p = 0.0565) at the femoral neck. At the lumbar spine, a higher number of lifetime menstrual cycles was also significantly associated with increased bone density (adjusted beta = 0.0010, p = 0.0052, partial r2 x 100 = 4.4%). This association was not significant after adjusting for age at menarche. Neither reproductive years (age - age at menarche) nor a history of irregular cycles (either at menarche, in the past year, or ever) was associated with bone density at either site. Menstrual function appears to affect the bone density of these young women. Studies that include measures of reproductive and pituitary hormones are needed to further explore the role of hormones in the potential link between menstrual history and bone density.

Colorectal cancer: another complication of diabetes mellitus?

Delayed stool transit and other gastrointestinal abnormalities are commonly observed in persons with diabetes mellitus and are also known to be associated with colorectal cancer. Previous studies of the contribution of diabetes to colorectal cancer incidence and mortality have been limited by small sample sizes and failure to adjust for covariates. With more than 1 million respondents, the 1959-1972 Cancer Prevention Study provided a unique opportunity to explore whether persons with diabetes (n=15,487) were more likely to develop colorectal cancer during a 13-year follow-up period than were persons without diabetes (n=850,946). After adjustment for colorectal cancer risk factors, such as race, educational level, body mass index, smoking, alcohol use, dietary intake, aspirin use, physical activity, and family history of colorectal cancer, the incidence density ratio comparing colorectal cancer in those with diabetes and those without diabetes was 1.30 (95% confidence interval 1.03-1.65) for men and 1.16 (95% confidence interval 0.87-1.53) for women. However, diabetes was not associated with greater case fatality. Future studies should explore the possibility of a cancer-promoting gastrointestinal milieu, including delayed stool transit and elevated fecal bile acid concentrations, associated with hyperglycemia and diabetic neuropathy.

Trends in overweight among US adults from 1987 to 1993: a multistate telephone survey

OBJECTIVES

Using data from the Behavioral Risk Factor Surveillance System, this study describes trends in the prevalence of overweight between 1987 and 1993.

METHODS

Data were examined from 33 states participating in an ongoing telephone survey of health behaviors of adults (n = 387,704). Self-reported weights and heights were used to calculate sex-specific prevalence estimates of overweight for each year from 1987 to 1993. Time trends were evaluated with the use of linear regression.

RESULTS

Between 1987 and 1993, the age-adjusted prevalence of overweight increased by 0.9% per year for both sexes (from 21.9% to 26.7% among men and from 20.6% to 25.4% among women). The increasing linear trend was observed in all subgroups of the population but was most notable for Black men (1.5% per year) and men living in the Northeast (1.4% per year). Secular changes in smoking and leisure-time physical activity did not entirely account for the increase in overweight.

CONCLUSIONS

The prevalence of overweight among American adults increased by 5% between 1987 and 1993. Efforts are needed to explore the causes of this adverse trend and to find effective strategies to prevent obesity.