Recent population changes in HbA(1c) and fasting insulin concentrations among US adults with preserved glucose homeostasis.

AIMS/HYPOTHESIS: Although diagnosed type 2 diabetes has increased in the past decade, little is known about accompanying changes in fasting plasma glucose (FPG), HbA(1c) and fasting serum insulin (FI) levels in the non-diabetic population. METHODS: Using population estimates from National Health and Nutrition Examination Surveys, we compared distribution of FPG, HbA(1c) and FI in non-diabetic US persons who were >or=20 years old in 1999 to 2006 with that in persons of the same age in 1988 to 1994. RESULTS: Age-, sex- and race-adjusted mean FPG levels between the two study periods did not change, but mean HbA(1c) and FI levels increased (0.10% and 4.8 pmol/l, respectively; p < 0.001 for both). The increased HbA(1c) level was driven largely by an upward shift in the lower end of the HbA(1c) distribution. In contrast, the increased FI level was driven primarily by an upward shift in the middle and higher end of FI distribution, especially among persons aged 20 to 44 years. After adjustments for BMI or waist circumference, the increase in the mean HbA(1c) level was attenuated (0.06%; p < 0.001), whereas the mean FPG level decreased by 0.1 mmol/l (p < 0.001) and the mean FI level no longer demonstrated significant change. CONCLUSIONS/INTERPRETATION: Despite little change in the distribution of FPG levels, HbA(1c) and FI levels increased in the non-diabetic population in the past decade. The increase in FI levels suggests that levels of insulin resistance were greater among US adults, especially young adults, than in the previous decade.

Longitudinal changes in BMI and in an index estimating excess lipids among white and black adults in the United States.

BACKGROUND: Adult obesity prevalence is influenced by rates of weight gain or loss among individual persons, but few studies have measured individual weight change in large populations. Changes in weight may not coincide with changes in the lipid accumulation product (LAP), a continuous index derived from waist circumference and triglycerides concentration for estimating excess lipids. DESIGN AND MEASUREMENTS: Descriptive report of longitudinal changes from US studies that included body mass index (BMI, kg/m(2)) and LAP. SUBJECTS: A total of 16 763 white and black adults studied between 1989 and 1996 in three observational cohorts (Coronary Artery Risk Development in Young Adults, Atherosclerosis Risk in Communities Study and Cardiovascular Health Study). RESULTS: The means of individual annual changes in BMI were positive for young adults, but the mean changes were reduced at older ages (P for linear trend <0.001), becoming negative after 73-83 years old. These mean, individual changes in BMI, specific to sex and age, were approximately 0.1 U/year greater than those reported from previous, representative, longitudinal measurements collected in the United States between 1971 and 1984. Mean, individual annual changes in LAP were strongly positive before middle age. For men, the annual LAP changes were reduced at older ages (P linear trend <0.05). For women, they were greater at older ages (white women, P<0.001) or remained unchanged (black women, P>0.3). With increasing age, there was a greater proportion of persons whose positive LAP change was accompanied by simultaneous BMI change that was negative or zero. CONCLUSIONS: These longitudinal observations made during 1989-1996 suggest greater annual changes in BMI compared to an adult cohort studied during 1971-1984. As estimated by LAP, adults of all ages tended to accumulate excess lipids, including circumstances in which they lost weight.

The 10-year incidence of overweight and major weight gain in US adults.

We estimated the 10-year incidence of major weight gain (a gain in body mass index of greater than or equal to 5 kg/m2 and overweight (a body mass index of greater than or equal to 27.8 for men and greater than or equal to 27.3 for women) in US adults using data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. Persons aged 25 to 74 years at baseline were reweighed a decade after their initial examination (men, 3727; women, 6135). The incidence of major weight gain was twice as high in women and was highest in persons aged 25 to 34 years (men, 3.9%; women, 8.4%). Initially overweight women aged 25 to 44 years had the highest incidence of major weight gain of any subgroup (14.2%). For person not overweight at baseline (men, 2760; women, 4295), the incidence of becoming overweight was similar in both sexes and was highest in those aged 35 to 44 years (men, 16.3%; women, 13.5%). We conclude that obesity prevention should begin among adults in their early 20s and that special emphasis is needed for young women who are already overweight.

Health-related behaviors of women physicians vs other women in the United States.

OBJECTIVE: To examine the health-related behaviors of women physicians compared with those of other women of high and not high socioeconomic status and with national goals. METHODS: We examined the results of a questionnaire-based survey of a stratified random sample, the Women Physicians' Health Study, and a US telephone survey (Behavioral Risk Factor Surveillance System of the Centers for Disease Control and Prevention, Atlanta, Ga). We analyzed 3 samples of women aged 30 to 70 years: (1) respondents from the Women Physicians' Health Study (n = 4501); (2) respondents from the Behavioral Risk Factor Surveillance System (n = 1316) of the highest socioeconomic status; and (3) all other respondents from the Behavioral Risk Factor Surveillance System (n = 35,361). RESULTS: Women physicians were more likely than other women of high socioeconomic status and even more likely than other women not to smoke. The few physicians (3.7%) who smoked reported consuming fewer cigarettes per day, and physicians who had stopped smoking reported quitting at a younger age than women in the general population. Women physicians were less likely to report abstaining from alcohol, but those who drank reported consuming less alcohol per episode than other women and were less likely to report binging on alcohol than women in the general population. Unlike women in the general population and even other women of high socioeconomic status, women physicians' reported behaviors exceeded national goals for the year 2000 in all examined behaviors and screening habits. CONCLUSIONS: Women physicians report having generally good health habits even when compared with other socioeconomically advantaged women and report exceeding all examined national goals for personal screening practices and other personal health behaviors. Women physicians' behaviors may provide useful standards for other women in the United States.

Hyperinsulinemia predicts fatal liver cancer but is inversely associated with fatal cancer at some other sites: the Paris Prospective Study.

OBJECTIVE: To investigate whether insulin is a risk factor for death by site-specific cancers. RESEARCH DESIGN AND METHODS: This was a prospective cohort study of 6,237 nondiabetic French working men between ages 44 and 55 years at baseline from the Paris Prospective Study cohort. Death by site-specific cancers was investigated in relation to baseline insulin concentrations during fasting and 2 h after a 75-g oral glucose tolerance test. RESULTS: Of the original 6,237 men in the cohort, 1.739 died over the 23.8 years of follow-up. 778 (45%) from cancer. Baseline hyperinsulinemia, both fasting and 2-h, was significantly associated with fatal liver cancer, with age-adjusted standardized hazards ratios of 2.72 (95% CI 1.87-3.94) and 3.41 (2.23-5.21). In contrast, fasting hyperinsulinemia was inversely associated with fatal lip, oral cavity, and pharynx cancer and larynx cancer, with hazards ratios of 0.55 (0.41-0.75) and 0.63 (0.47-0.83), respectively; 2-h insulin concentrations were inversely associated with stomach and larynx cancers (hazards ratios 0.62 [0.43-0.90] and 0.66 [0.50-0.891, rcspectively). These relationships were stable after adjusting for other risk factors. Insulin concentrations remained negatively associated with deaths from these cancers in analyses restricted to men who smoked and in those who were not chronic alcohol consumers.

Vertex-corrected blood pressure in black girls. Relation to obesity, glucose, and cations.

Correlates of resting blood pressure (BP) were explored among 32 inner-city, black girls, ages 11.7 to 13.9 years, a sample drawn from the second and fourth quartiles of the BP distribution in an earlier school survey. Customary BP measurements in the seated position were corrected for the height of the arterial column extending from the BP cuff to the top (vertex) of each girl's head. This vertex correction procedure has previously been shown to eliminate the childhood association between mean arterial pressure and age. Vertex-corrected systolic BP was correlated individually (p less than 0.03) with serum fasting glucose, ionized calcium, sodium, and calculated osmolality. The BP association with serum glucose did not persist after an oral sucrose challenge. Vertex-corrected diastolic BP was correlated individually (p less than 0.02) with serum ionized calcium and four indices of obesity, the best correlated of which was the subscapular skinfold (r = 0.66, p = 0.0001). Vertex-corrected BPs generally provided stronger correlations than customary (uncorrected) BPs with the variables of interest. Correlations with seated BPs were generally stronger than those with supine BPs. By multiple regression analysis, seated vertex-corrected systolic BP was related directly to serum fasting glucose and ionized calcium and inversely to pulse rate (R2 = 0.53). Seated vertex-corrected diastolic BP was related directly to subscapular skinfold and calculated osmolality (R2 = 0.54). Vertex correction may facilitate clinical or epidemiological studies of early hypertension.

A major error in nomograms for estimating body mass index.

The Surgeon General's Report on Nutrition and Health and Diet and Health include a nomogram for determining body mass index (BMI, in kg/m2) when the subject's weight and height are known. I regret to report that the BMI in nomograms in these books are highly inaccurate when compared with direct calculations of BMI. Anyone wishing to use a nomogram for the rapid estimation of BMI should be cautioned against relying on the versions that appear in these books.

Is race associated with weight change in US adults after adjustment for income, education, and marital factors?

We examined the 10-y change in body mass index (BMI, in kg/m2) of black and white adults who entered the First National Health and Nutrition Examination Survey Epidemiologic Followup Study at ages 25-44 y. In women the mean change in BMI was greater for blacks than for whites despite multiple adjustments. However, the risk of major weight gain (MWG; BMI change greater than or equal to + 5) was nearly identical in black and white women. Womens' MWG was independently associated with low income [odds ratio (OR) = 1.7] and with becoming married (OR = 1.8). The risk of major weight loss (MWL; BMI change less than or equal to -2.5) was lower in black women than in white women (OR = 0.6). In men mean BMI change, MWG (BMI change greater than or equal to + 4) and MWL (BMI change greater than or equal to -2) were not associated with race, but there were effects associated with low income, low education, and marital changes. Black race does not increase the risk of weight gain; in women it may be associated with a reduced likelihood of weight loss.

The 10-y incidence of obesity and major weight gain in black and white US women aged 30-55 y.

Although the prevalence of obesity in US women is well-described, data are limited on the incidence of major weight gain and obesity. We used data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study to estimate the 10-y incidence of major weight gain (greater than or equal to 10 kg) and obesity [body mass index (BMI, in kg/m2) greater than or equal to 29] in a cohort of US women aged 30-55 y (n = 535 blacks and 2976 whites). In women not obese at baseline, blacks were 60% more likely to become obese than whites [incidence in blacks = 15.5%, 95% confidence interval (CI) = 11.2-19.7; incidence in whites = 9.7%, 95% CI = 8.6-10.8]. This higher incidence of obesity in blacks was largely due to their higher average BMI at baseline. The incidence of major weight gain was 50% higher in blacks than in whites (in blacks, 17.3%; 95% CI = 13.6-21.0; in whites, 11.7%; 95% CI = 10.3-13.1). We estimate that in black and white women, respectively, 16% and 12% of coronary heart disease is attributed to major weight gain whereas 35% and 21% is attributed to being obese.

The abdominal diameter index and sudden coronary death in men.

Alternative anthropometric indexes were compared for their ability to discriminate between 35 Atlanta men with sudden coronary death and 81 male controls. With or without adjustments for age, race, and body mass index, the abdominal diameter index (supine sagittal abdominal diameter divided by midthigh circumference) was associated with sudden coronary death more strongly than the waist/hip ratio or waist/thigh ratio of circumferences.

Choosing an index for abdominal obesity: an opportunity for epidemiologic clarification.

Despite numerous reports that abdominal obesity is related to disease risk, the study of body-fat distribution remains a largely empirical science. Elucidation of the pathophysiologic linkage between abdominal obesity and disease would be better served by generating hypotheses and testing them--the process of deductive science. Physiologists have proposed that adipose tissue of the intra-abdominal compartment (that drained by the portal vein) contributes strongly to atherosclerosis. If this is so, then the volume of the intra-abdominal fat depot might be better correlated with disease states than a less specific anthropometric index such as the waist-to-hip girth ratio. Alternative abdominal-obesity indices (e.g. sagittal abdominal diameter divided by thigh girth) could be tested in epidemiologic studies to improve our pathophysiologic understanding of how body-fat distribution is related to atherosclerosis and other diseases.

Simple anthropometric indices associated with ischemic heart disease.

In a case-control study of 217 hospitalized incident cases of ischemic heart disease and 261 controls we compared various anthropometric indices for the strength of their associations to the outcome event. The ratio of supine sagittal abdominal diameter to midthigh girth ("abdominal diameter index"; ADI) was the simple index that best discriminated cases from controls for both men (standardized difference, 0.65; p < 0.0001) and women (standardized difference, 0.95; p < 0.0001). The waist-to-thigh ratio of girths (WTR) (standardized difference, 0.57 and 0.90; p < 0.0001) was nearly as strong as the ADI and stronger than the traditional waist-to-hip ratio (standardized difference, 0.34 and 0.68; p < 0.005). After adjustments for age and race, the men's odds ratio for ischemic heart disease (tertile 3 vs. tertile 1) was 5.5 (95% CI, 2.9-10) using ADI and 5.1 (2.6-10) using the WTR. The women's odds ratio was 6.3 (1.9-20) using ADI and 8.7 (2.3-33) using the WTR. Further adjustments for body mass index and cardiovascular risk factors did not substantially change these risk estimates. Similar odds ratios were estimated by analyses restricted to 169 neighborhood-matched case-control pairs. In contrast, increased midthigh girth and subcutaneous fat mass (sum of three skinfolds) were associated with a protective effect against ischemic heart disease. Anthropometry using the ADI or WTR could offer a low-cost, noninvasive method for the clinical or epidemiologic evaluation of ischemic heart disease risk.

Are geographic regions with high income inequality associated with risk of abdominal weight gain?

Geographic regions characterized by income inequality are associated with adverse mortality statistics, but the pathophysiologic mechanisms that mediate this ecologic relationship have not been elucidated. This study used a United States mail survey of 34158 male and 42741 female healthy-adult volunteers to test the association between residence in geographic regions with relative income inequality and the likelihood of weight gain at the waist. Respondents came from 21 states that were characterized by the household income inequality (HII) index, a measure reflecting the proportion of total income received by the more well off 50% of households in the state. The main outcome measure was self-reported weight gain mainly at the waist as opposed to weight gain at other anatomic sites. After controlling for age, other individual-level factors, and each state's median household income, men's likelihood of weight gain at the waist was positively associated (p = 0.0008) with the HII index. Men from states with a high HII (households above the median receive 81.6% to 82.6% of the income) described weight gain at the waist more often than men from states with a low HII (households above the median receive 77.0% to 78.5% of the income) (odds ratio = 1.12, 95% confidence interval 1.03 to 1.22). Women's results showed a non-significant trend in the same direction. An association between ecologically defined socio-environmental stress and abdominal obesity may help to clarify the pathophysiologic pathways leading to several major chronic diseases.

A review of the association between abdominal fat distribution, health outcome measures, and modifiable risk factors.

PURPOSE OF THE REVIEW. This review of the literature examines the relationship between abdominal fat distribution and specific health outcome measures, modifiable risk factors, the impact of intervention efforts, and the significance of measurement methods. SEARCH METHODS USED. The research material that was received was found through several on-line data bases, including MEDLINE and CINAHL, an examination of references from selected articles, a manual review of recent relevant journals, and interviews with several physicians and epidemiologists who are experts in this field of inquiry. Forty-three research articles were reviewed for the section on health risk outcomes and abdominal fat distribution. Twenty studies were reviewed in the section on modifiable variables associated with fat distribution. Finally, 10 studies which examined the effect of behavior change on fat distribution were included in this review. SUMMARY OF IMPORTANT FINDINGS. Recent research indicates that people whose body fat is deposited more in the central or abdominal area, especially the intra-abdominal area, than it is in the gluteofemoral area are at increased risk for cardiovascular disease. This risk is independent of, but exacerbated by, the degree of obesity. Several nonmodifiable factors such as age, gender, and menopause as well as some modifiable factors such as obesity, smoking, physical inactivity, and alcohol intake are positively associated with abdominal fat deposition. MAJOR CONCLUSIONS. Intervention results indicate that it is possible to decrease abdominal fat with total weight loss or smoking cessation.

Dental disease and risk of coronary heart disease and mortality.

OBJECTIVE: To investigate a reported association between dental disease and risk of coronary heart disease. SETTING: National sample of American adults who participated in a health examination survey in the early 1970s. DESIGN: Prospective cohort study in which participants underwent a standard dental examination at baseline and were followed up to 1987. Proportional hazards analysis was used to estimate relative risks adjusted for several covariates. MAIN OUTCOME MEASURES: Incidence of mortality or admission to hospital because of coronary heart disease; total mortality. RESULTS: Among all 9760 subjects included in the analysis those with periodontitis had a 25% increased risk of coronary heart disease relative to those with minimal periodontal disease. Poor oral hygiene, determined by the extent of dental debris and calculus, was also associated with an increased incidence of coronary heart disease. In men younger than 50 years at baseline periodontal disease was a stronger risk factor for coronary heart disease; men with periodontitis had a relative risk of 1.72. Both periodontal disease and poor oral hygiene showed stronger associations with total mortality than with coronary heart disease. CONCLUSION: Dental disease is associated with an increased risk of coronary heart disease, particularly in young men. Whether this is a causal association is unclear. Dental health may be a more general indicator of personal hygiene and possibly health care practices.

The population distribution of the sagittal abdominal diameter (SAD) and SAD/height ratio among Finnish adults.

Sagittal abdominal diameter (SAD; 'abdominal height' measured in supine position) may improve upon conventional anthropometry for predicting incident cardiometabolic diseases. However, the SAD is used infrequently by practitioners and epidemiologists. A representative survey of Finnish adults in 2000-2001 collected body measurements including SAD (by sliding-beam calliper) using standardized protocols. Sampled non-pregnant adults (ages 30+ years; 79% participation) provided 6123 SAD measurements from 80 health centre districts. Through stratified, complex survey design, these data represented 2.86 million adults at ages 30+ years. SAD ranged from 13.5 to 38.0 cm, with a population mean (standard error) of 21.7 (0.05) cm and median (interquartile range) of 21.0 (19.1-23.4). Median SAD was higher at ages 50+ years compared with ages 30-49 both for men (22.4 [20.5-24.6] vs. 20.8 [19.3-22.7]) and women (21.7 [19.6-23.9] vs. 19.4 [17.8-21.4]). The SAD/height ratio was similar (0.118) for both sexes at 30-39 years, rising more steeply with age for women than men. Attaining only a basic education, compared with a high level, was associated with increased mean (95% confidence interval) SADs for men (22.6 [22.3-22.8] vs. 22.0 [21.7-22.2]) and women (21.8 [21.5-22.0] vs. 20.6 [20.4-20.8]). Finland's early experience with nationally representative SAD measurements provides normative reference values and physiological insights useful for investigations of cardiometabolic risk.

Comparison of two waist circumference measurement protocols: the SEARCH for diabetes in youth study.

BACKGROUND: Reports comparing waist circumference (WC) measurements from young populations are scarce. OBJECTIVES: We compared two protocols for measuring waist circumference in a sample of youth with diabetes. METHODS: Participants were enrolled in the SEARCH for Diabetes in Youth Study (SEARCH). WC was measured at least twice by the National Health and Nutrition Examination Survey (NHANES) protocol and twice by the World Health Organization (WHO) protocol. Method-specific averages were used in these analyses. RESULTS: Among 6248 participants, the mean NHANES WC (76.3 cm) was greater than the mean WHO WC (71.9 cm). Discrepancies between protocols were greater for females than males, among older participants, and in those with higher body mass index (BMI). In both sexes and four age strata, the WCs using either method were highly correlated with BMI z-score. The within-method differences between the first and second measurements were similar for the two methods. CONCLUSIONS: These analyses do not provide evidence that one of these two methods is more reproducible or is a better indicator of obesity as defined by BMI z-scores.

Prenatal environmental exposures that may influence ß-cell function or insulin sensitivity in middle age.

The associations between fetal environment and diabetes risk are likely mediated by the offspring's diminished pancreatic ß-cell function or reduced insulin sensitivity. Our ability to distinguish between these mechanisms is impeded by the lack of markers describing an individual's gestational environment. Fingerprints, however, are permanently fixed in the first half of gestation, and increased values of a dermatoglyphic marker that contrasts fingerprint ridge counts between the thumbs and fifth fingers (Md15) have been linked to type 2 diabetes. Among 763 adults without known diabetes from the Dutch Hunger Winter Families Study, we tested the associations of Md15 with homeostatic assessment indices of ß-cell function (HOMA-b) and insulin sensitivity (QUICKI). For either outcome index, linear regression models included terms for Md15 tertiles and for maternal history of diabetes as reported by each participant. All models were corrected for sibling pairs and adjusted for age, sex and famine exposures. Increased Md15 was associated with decreased HOMA-b (P = 0.03 for Md15 tertile 3 v. 1) but not with QUICKI. In contrast, maternal history of diabetes was associated with decreased QUICKI (P < 0.001) but not with HOMA-b. Birth weight (available for 520 participants) was positively associated with increased QUICKI (P = 0.04 for birth weight tertile 3 v. 1) but not with HOMA-b. Fingerprint Md15, maternal history of diabetes and birth weight may help to identify specific defects in the control of adult glucose metabolism. Research into the environment associated with Md15 variation may suggest prenatal strategies for optimizing ß-cell function in adult life.