Fatty liver indices in the multiethnic United States National Health and Nutrition Examination Survey

BACKGROUND

Validated non-invasive measures of fatty liver are needed that can be applied across populations and over time. A fatty liver index (FLI) including body mass index, waist circumference, triglycerides and gamma glutamyltransferase (GGT) activity was developed in an Italian municipality, but has not been validated widely or examined in a multiethnic population.

AIMS

We evaluated this FLI in the multiethnic U.S. National Health and Nutrition Examination Survey (NHANES) and also to explore whether an improved index for the U.S. population (US FLI) could be derived. The US FLI would then used to examine U.S. time trends in fatty liver prevalence.

METHODS

We studied 5869 fasted, viral hepatitis negative adult participants with abdominal ultrasound data on fatty liver in the 1988-1994 NHANES. Time trend analyses included 21 712 NHANES 1988-1994 and 1999-2012 participants.

RESULTS

The prevalence of fatty liver was 20%. For the FLI, the area under the receiver operating characteristic curve [AUC; 95% confidence interval (CI)] was 0.78 (0.74-0.81). The US FLI included age, race-ethnicity, waist circumference, GGT activity, fasting insulin and fasting glucose and had an AUC (95% CI) of 0.80 (0.77-0.83). Defining fatty liver as a US FLI ≥ 30, the prevalence increased from 18% in 1988-1991 to 29% in 1999-2000 to 31% in 2011-2012.

CONCLUSIONS

For predicting fatty liver, the US FLI was a modest improvement over the FLI in the multiethnic U.S. population. Using this measure, the fatty liver prevalence in the U.S. population increased substantially over two decades.

Silymarin use and liver disease progression in the Hepatitis C Antiviral Long-Term Treatment against Cirrhosis trial

BACKGROUND

Silymarin is the most commonly used herbal product for chronic liver disease; yet, whether silymarin protects against liver disease progression remains unclear.

AIM

To assess the effects of silymarin use on subsequent liver disease progression in 1049 patients of the Hepatitis C Antiviral Long-Term Treatment against Cirrhosis (HALT-C) trial who had advanced fibrosis or cirrhosis and had failed prior peginterferon plus ribavirin treatment.

METHODS

Patients recorded their use of silymarin at baseline and were followed up for liver disease progression (two point increase in Ishak fibrosis score across baseline, year 1.5, and year 3.5 biopsies) and over 8.65 years for clinical outcomes.

RESULTS

At baseline, 34% of patients had used silymarin, half of whom were current users. Use of silymarin was associated (P < 0.05) with male gender; oesophageal varices; higher ALT and albumin; and lower AST/ALT ratio, among other features. Baseline users had less hepatic collagen content on study biopsies and had less histological progression (HR: 0.57, 95% CI: 0.33-1.00; P-trend for longer duration of use=0.026). No effect was seen for clinical outcomes.

CONCLUSIONS

Silymarin use among patients with advanced hepatitis C-related liver disease is associated with reduced progression from fibrosis to cirrhosis, but has no impact on clinical outcomes (Clinicaltrials.gov #NCT00006164).

Database comparison of the adult-to-adult living donor liver transplantation cohort study (A2ALL) and the SRTR U.S. Transplant Registry

Data submitted by transplant programs to the Organ Procurement and Transplantation Network (OPTN) are used by the Scientific Registry of Transplant Recipients (SRTR) for policy development, performance evaluation and research. This study compared OPTN/SRTR data with data extracted from medical records by research coordinators from the nine-center A2ALL study. A2ALL data were collected independently of OPTN data submission (48 data elements among 785 liver transplant candidates/recipients; 12 data elements among 386 donors). At least 90% agreement occurred between OPTN/SRTR and A2ALL for 11/29 baseline recipient elements, 4/19 recipient transplant or follow-up elements and 6/12 donor elements. For the remaining recipient and donor elements, >10% of values were missing in OPTN/SRTR but present in A2ALL, confirming that missing data were largely avoidable. Other than variables required for allocation, the percentage missing varied widely by center. These findings support an expanded focus on data quality control by OPTN/SRTR for a broader variable set than those used for allocation. Center-specific monitoring of missing values could substantially improve the data.

Recipient morbidity after living and deceased donor liver transplantation: findings from the A2ALL Retrospective Cohort Study

Patients considering living donor liver transplantation (LDLT) need to know the risk and severity of complications compared to deceased donor liver transplantation (DDLT). One aim of the Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL) was to examine recipient complications following these procedures. Medical records of DDLT or LDLT recipients who had a living donor evaluated at the nine A2ALL centers between 1998 and 2003 were reviewed. Among 384 LDLT and 216 DDLT, at least one complication occurred after 82.8% of LDLT and 78.2% of DDLT (p = 0.17). There was a median of two complications after DDLT and three after LDLT. Complications that occurred at a higher rate (p < 0.05) after LDLT included biliary leak (31.8% vs. 10.2%), unplanned reexploration (26.2% vs. 17.1%), hepatic artery thrombosis (6.5% vs. 2.3%) and portal vein thrombosis (2.9% vs. 0.0%). There were more complications leading to retransplantation or death (Clavien grade 4) after LDLT versus DDLT (15.9% vs. 9.3%, p = 0.023). Many complications occurred more commonly during early center experience; the odds of grade 4 complications were more than two-fold higher when centers had performed <or=20 LDLT (vs. >40). In summary, complication rates were higher after LDLT versus DDLT, but declined with center experience to levels comparable to DDLT.

Relationship of serum leptin concentration and other measures of adiposity with gallbladder disease

Obesity increases the risk of gallstones, especially in women. Most gallbladder disease studies have used body mass index (BMI) as a measure of overall adiposity, although BMI does not distinguish between fat and lean body mass. Central adiposity may also increase gallstone risk, although this is less well studied. Leptin is a peptide whose serum concentration is highly correlated with total body fat mass. We examined the relationship of gallbladder disease with anthropometric measures and serum leptin concentration in a large, national, population-based study. A total of 13,962 adult participants in the Third National Health and Nutrition Examination Survey underwent gallbladder ultrasonography and anthropometric measurements of BMI, body circumferences, and skinfold thicknesses, and a random subgroup of 5,568 had measures of fasting serum leptin concentrations. Gallstone-associated gallbladder disease was defined as ultrasound-documented gallstones or evidence of cholecystectomy. When controlling for BMI and other gallbladder disease risk factors in multivariate analysis, a test for trend for increasing waist-to-hip circumference ratio and risk of gallbladder disease was statistically significant among women (P =.043) and men (P =.007). BMI remained strongly associated with gallbladder disease among women (P <.001), but was unrelated among men (P =.46). Leptin concentration was associated with gallbladder disease in both sexes (P <.001), but not after controlling for BMI and waist-to-hip circumference in either women (P =.29) or men (P =.65). In conclusion, waist-to-hip circumference ratio was related to gallbladder disease among women and men. Serum leptin concentration was not a better predictor of gallbladder disease than anthropometry.

Hospitalization with respiratory disease following hiatal hernia and reflux esophagitis in a prospective, population-based study

PURPOSE

Hiatal hernia and reflux esophagitis have been associated with respiratory manifestations, though the temporal sequence of this relationship is uncertain. This study examined prospectively the relationship of hiatal hernia and reflux esophagitis with respiratory outcomes in a representative sample of the United States population.

METHODS

6928 participants in the first National Health and Nutrition Examination Survey, a population-based sample initially examined in 1971-1975, who were hospitalized during follow-up through 1992-1993 composed the study population. The relationship between hiatal hernia and reflux esophagitis hospitalization and a subsequent hospitalization with respiratory outcomes was measured in persons free of respiratory disease at baseline and at first hospitalization.

RESULTS

Multivariable survival analysis showed higher rates of hospitalization with any respiratory diagnosis [rate ratio (RR) = 1.4, 95% confidence interval (CI) 1.2-1.7] in persons with preceding hiatal hernia or reflux esophagitis hospitalization. Individually, rate ratios of pharyngitis (RR = 5.6, CI 2.0-15.7), tonsillitis (RR = 8.0, CI 2.5-25.8), bronchitis (RR = 1.8, CI 1.2-2.7), pneumonia (RR = 1.3, CI 1.0-1.7), emphysema (RR = 2.9, CI 1.5-5.5), asthma (RR = 2.1, CI 1.1-4.2), bronchiectasis (RR = 6.2, CI 1.1-34.3), and empyema or abscess (RR = 7.4, CI 1.3-42.3) were all higher following hiatal hernia and reflux esophagitis. Rate ratios were similar when reflux esophagitis and hiatal hernia were examined separately.

CONCLUSIONS

A prior hiatal hernia or reflux esophagitis hospitalization increased risk of respiratory disease hospitalization.

Leptin concentrations in the United States: relations with demographic and anthropometric measures

BACKGROUND

Leptin is a peptide that is strongly correlated with adiposity and is a potential determinant of obesity and its complications.

OBJECTIVE

Leptin concentrations from a representative sample of the US population were examined in relation to demographic and anthropometric measures.

DESIGN

Fasting serum leptin concentrations were measured in 6303 women and men aged > or =20 y in the third National Health and Nutrition Examination Survey. Anthropometric measures included body mass index, 4 skinfold thicknesses, and 4 body circumferences. Ethnic groups included non-Hispanic whites and blacks and Mexican Americans.

RESULTS

The mean serum leptin concentration was much higher in women (12.7 microg/L) than in men (4.6 microg/L). In a multivariate analysis, leptin concentrations were associated with the sum of 4 skinfold thicknesses, waist and hip circumferences, ethnicity, and age. These measures explained most of the variance in leptin concentrations in women (R2 = 0.69) and in men (R2 = 0.67). Triceps skinfold thickness, when substituted for the sum of skinfold thicknesses, performed nearly as well in women (R2 = 0.68) and men (R2 = 0.67). Leptin concentrations were slightly but significantly higher in non-Hispanic blacks than in non-Hispanic whites of both sexes when these anthropometric measures and age were controlled for; Mexican Americans had concentrations that were intermediate compared with the concentrations of non-Hispanic whites and blacks.

CONCLUSIONS

In this large, representative sample of the US population, demographic and anthropometric measures predicted serum leptin concentrations in women and men.

The role of diabetes in hepatocellular carcinoma: a case-control study among United States Veterans

OBJECTIVE

Diabetes mellitus (DM) has been reported to increase the risk of hepatocellular carcinoma (HCC). We carried out a case-control study to examine the role of DM while controlling for several known risk factors of HCC.

METHODS

All hospitalized patients with primary liver cancer (PLC) during 1997-1999 were identified in the computerized database of the Department of Veterans Affairs, the Patient Treatment File. Controls without cancer were randomly assigned from the Patient Treatment File during the same time period. The inpatient and outpatient files were searched for several conditions including DM, hepatitis C virus (HCV), hepatitis B virus (HBV), alcoholic cirrhosis, autoimmune hepatitis, hemochromatosis, and nonspecific cirrhosis. Adjusted odds ratios (OR) were calculated in a multivariable logistic regression model.

RESULTS

We identified 823 patients with PLC and 3459 controls. The case group was older (62 yr [+/-10] vs 60 [+/-11], p < 0.0001), had more men (99% vs 97%, 0.0004), and a greater frequency of nonwhites (66% vs 71%, 0.0009) compared with controls. However, HCV- and HBV-infected patients were younger among cases than controls. Risk factors that were significantly more frequent among PLC cases included HCV (34% vs 5%, p < 0.0001), HBV (11% vs 2%, p < 0.0001), alcoholic cirrhosis (47% vs 6%, p < 0.0001), hemochromatosis (2% vs 0.3%, p < 0.0001), autoimmune hepatitis (5% vs 0.5%, p < 0.0001), and diabetes (33% vs 30%, p = 0.059). In the multivariable logistic regression, diabetes was associated with a significant increase in the adjusted OR of PLC (1.57, 1.08-2.28, p = 0.02) in the presence of HCV, HBV, or alcoholic cirrhosis. Without markers of chronic liver disease, the adjusted OR for diabetes and PLC was not significantly increased (1.08, 0.86-1.18, p = 0.4). There was an increase in the HCV adjusted OR (17.27, 95% Cl = 11.98-24.89) and HBV (9.22, 95% CI = 4.52-18.80) after adjusting for the younger age of HCV- and HBV-infected cases. The combined presence of HCV and alcoholic cirrhosis further increases the risk with an adjusted OR of 79.21 (60.29-103.41). The population attributable fraction for HCV among hospitalized veterans was 44.8%, whereas that of alcoholic cirrhosis was 51%.

CONCLUSION

DM increased the risk of PLC only in the presence of other risk factors such as hepatitis C or B or alcoholic cirrhosis. Hepatitis C infection and alcoholic cirrhosis account for most of PLC among veterans.

Gallstones and ethnicity in the Americas

Information on ethnicity as related to gallstones has been limited by insufficient or inaccurate characterization of ethnicity. Nevertheless, in recent years, ultrasonography has allowed limited examination of ethnic differences in the risk of gallbladder disease, defined by a history of cholecystectomy or ultrasonographic detection of gallstones. Among women, the risk of gallbladder disease is highest among American Indians, followed by Hispanics, non-Hispanic whites, and non-Hispanic blacks. Men differ from women by having lower risk in all ethnic groups and by having a similar prevalence between Hispanics and non-Hispanic whites. It does not appear that the type of stone differs much according to ethnic group in the United States. Well-known risks for gallbladder disease, such as obesity, weight loss, pregnancy, and low alcohol use do not explain differences in ethnic risk. As yet, genetic markers have not been identified that would explain differences in risk among ethnic groups. Higher case fatality rates among non-Hispanic blacks than non-Hispanic whites suggest that blacks may have inadequate access to medical care for gallbladder disease.

Relationship of iron-deficiency anemia with esophagitis and hiatal hernia: hospital findings from a prospective, population-based study

OBJECTIVE

Iron-deficiency anemia is sometimes attributed to esophagitis and hiatal hernia; however, because these GI conditions are so common, such an association could be coincidental. We examined prospectively whether esophagitis and hiatal hernia increased the risk of iron-deficiency anemia in a national, population-based study.

METHODS

The study population comprised 5069 adult participants in the first National Health and Nutrition Examination Survey, who were free of GI hemorrhage and anemia at baseline examination in 1971-1975 and who were hospitalized at some point during nearly 20 yr of follow-up. Rates of hospitalization with iron-deficiency or unspecified anemia were compared between patients with a hospital diagnosis of esophagitis or hiatal hernia and those who had not yet had a diagnosis of these disorders. Adjusted rate ratios were calculated using time-dependent, multivariable, proportional hazards analysis.

RESULTS

During follow-up, 59 patients were hospitalized with esophagitis alone, 140 with hiatal hernia alone, and 70 with both diagnoses. A total of 102 participants were hospitalized with iron-deficiency anemia and 256 with unspecified anemia. Compared to those without a diagnosis of esophagitis or hiatal hernia, patients with a diagnosis of hiatal hernia had higher rates of subsequent hospitalization with iron-deficiency anemia. The hazard rate ratio (HRR) for hiatal hernia was 2.9 (95% confidence interval, 1.5-5.5). A trend was found for esophagitis with a HRR of 2.2 (95% confidence interval, 0.79-6.0). Results were similar with unspecified anemia as the outcome.

CONCLUSIONS

Hiatal hernia should be considered as a possible cause of iron-deficiency anemia. The relationship of esophagitis with iron-deficiency anemia requires further study.

Association of coffee consumption with gallbladder disease

Coffee consumption was recently shown to protect against symptomatic gallbladder disease in men. The authors examined the relation of ultrasound-documented gallbladder disease with coffee drinking in 13,938 adult participants in the Third National Health and Nutrition Examination Survey, 1988-1994. The prevalence of total gallbladder disease was unrelated to coffee consumption in either men or women. However, among women a decreased prevalence of previously diagnosed gallbladder disease was found with increasing coffee drinking (p = 0.027). These findings do not support a protective effect of coffee consumption on total gallbladder disease, although coffee may decrease the risk of symptomatic gallstones in women.

Improved survival after variceal hemorrhage over an 11-year period in the Department of Veterans Affairs

OBJECTIVES

Over the past two decades, several modalities have become widely used in the management of esophageal variceal hemorrhage. The effectiveness of these measures on the outcome of patients with this type of hemorrhage remains unknown.

METHODS

Using the Department of Veterans Affairs (VA) Patient Treatment File, we identified two cohorts of patients diagnosed with an initial variceal hemorrhage: an early cohort during 1981-1982 (1339 patients), and a late cohort during 1988-1991 (3636 patients). Each cohort was followed for 6 yr for rebleeding and death. Analyses were performed with proportional hazards survival analysis controlling for confounding factors.

RESULTS

On presentation, patients in the late cohort were older (57 yr vs 55 yr, p < 0.0001) and had more ascites (25% vs 13%, p < 0.0001), more peritonitis (4% vs 2%, p < 0.0001), and more encephalopathy (14% vs 9%, p = 0.0003). The late cohort experienced a significant decline in mortality at 30 days (20.8% vs 29.6%, p = 0.0001) and at 6 yr (69.7% vs 74.5%, p = 0.0001). This improvement was accentuated in multivariate survival analysis when controlling for the more severe illness in the late cohort. For patients who survived the first 30 days, no significant difference in 6-yr mortality was found on univariate analysis between the early cohort (63.7%) and late cohort (61.8%) (p = 0.25), but survival was slightly better in the late cohort on multivariate analysis (p = 0.01). In the late cohort, patients with sclerotherapy during the initial hospitalization had better 30-day (17%) and 6-yr mortality (68%) than did the rest of the late cohort.

CONCLUSIONS

Between the years 1981-1982 and 1988-1991, improvements in long-term survival after an initial episode of esophageal variceal hemorrhage resulted primarily from better short-term mortality. Sclerotherapy offers a partial explanation for improved survival.

Recent developments in the epidemiology of Helicobacter pylori

Prevalence determinations have been performed around the world, and regardless of how exotic a location, H. pylori is found in a substantial proportion of the population. H. pylori remains among the most universal of infections. Understanding of some features of infection has changed. Infection can be gained and lost at rates higher than previously realized. Oral-oral and oral-fecal transmission account for most, if not nearly all, cases of infection. H. pylori infection has declined rapidly in developed countries, which probably has contributed to declines in duodenal ulcer disease and gastric cancer. The full health implications of the potential elimination of infection are unknown.

Food intake patterns and gallbladder disease in Mexican Americans

OBJECTIVE

Results of previous studies on diet and gallbladder disease (GBD), defined as having gallstones or having had surgery for gallstones, have been inconsistent. This research examined patterns of food intake in Mexican Americans and their associations with GBD.

DESIGN

Cross-sectional.

SUBJECTS

The study population included 4641 Mexican Americans aged 20-74 years who participated in the 1988-94 third National Health and Nutrition Examination Survey (NHANES III). GBD was diagnosed by ultrasound. Food intake patterns were identified by principal components analysis based on food frequency questionnaire responses. Component scores representing the level of intake of each pattern were categorized into quartiles, and prevalence odds ratios (POR) were estimated relative to the lowest quartile along with 95% confidence intervals (CI).

RESULTS

There were four distinct patterns in women (vegetable, high calorie, traditional, fruit) and three in men (vegetable, high calorie, traditional). After age adjustment, none were associated with GBD in women. However, men in the third (POR = 0.42, 95%CI 0.21-0.85) and fourth (POR = 0.53, 95%CI 0.28-1.01) quartiles of the traditional intake pattern were half as likely to have GBD as those in the lowest quartile.

CONCLUSIONS

These findings add to a growing literature suggesting dietary intake patterns can provide potentially useful and relevant information on diet-disease associations. Nevertheless, methods to do so require further development and validation.

Influence of parental height and sociodemographic factors on adolescent height in Brazil

OBJECTIVE

To analyze the influence of parental stature and environmental factors on the stature of adolescents from a national survey sample.

METHODS

A nationwide survey was carried out in 1989 among a stratified, two-stage, probability cluster sample of 14,455 Brazilian households to provide estimates of anthropometric deficits for urban and rural populations from the five regions of the country. Stature was measured for 5681 boys and girls age 14-18 years, 78.9% of their fathers, and 93.8% of their mothers. Associations between explanatory variables and adolescent height in centimeters were assessed by fitting multiple linear models to the data.

RESULTS

The predicted effects of parental stature and environmental conditions together sum to a total of 17 cm when comparing a boy born to parents with stature below the median and living in the underdeveloped rural Northeast region (1.56 m) with one born to parents with stature above the median and living in the partially industrialized urban South region (1.73 m). For girls, this estimated difference was 12 cm. For boys, the overall influence of parents' stature was 10 cm (R(2)= 0.40) and the sociodemographic factors had an overall influence of 7 cm (R(2) = 0.29). For girls, these values were 7 cm (R(2)= 0.35) for the parental influence and 5 cm (R(2) = 0.11) for the sociodemographic factors.

CONCLUSIONS

Mother's stature had the same influence on adolescent's stature as father's stature. Independent of parental stature, environmental factors have a strong influence on adolescent stature, particularly among boys.

Country of birth and prevalence of gallbladder disease in Mexican Americans

OBJECTIVES

This research sought to describe the association between country of birth and gallbladder disease (GBD) in Mexican Americans, identify subgroups at especially high risk, and identify risk factors that may mediate a birthplace-GBD association.

DESIGN

Cross-sectional.

METHODS

Our study population included 4157 Mexican Americans aged 20-74 who participated in the 1988-94 third National Health and Nutrition Examination Survey. GBD was diagnosed by ultrasound. Information on country of birth, education, income, and selected GBD risk factors was obtained from interviews. Prevalence odds ratios (POR) for GBD in Mexico- vs. US-born Mexican Americans were estimated by unconditional logistic regression, along with 95% confidence intervals (CI). To evaluate the extent to which GBD risk factors mediated the birthplace-GBD association, PORs for country of birth were compared in models with and without additional covariates.

RESULTS

Age-adjusted GBD prevalence was lower in Mexico- than in US-born Mexican-American women (POR = 0.70, 95% CI 0.50, 0.98) and men (POR = 0.63, 95% CI 0.40, 0.97). The difference was especially pronounced among subjects of lower socioeconomic status. Despite substantial differences in GBD risk factor distributions by birthplace, none could completely explain the prevalence difference.

CONCLUSIONS

The observation that GBD prevalence is higher among US-born Mexican Americans is consistent with research showing poorer health in this group. Further research is needed to identify strategies for reducing morbidity from GBD in Mexican Americans.

Seroprevalence and ethnic differences in Helicobacter pylori infection among adults in the United States

The seroprevalence of Helicobacter pylori infection was examined in the adult US population and among different ethnic groups. Stored sera from 7465 adult participants in the first phase of the third National Health and Nutritional Examination Survey (1988-1991) were tested with a sensitive and specific IgG ELISA, to diagnose infection. Seroprevalence of H. pylori among all participants was 32. 5%. This increased with age, from 16.7% for persons 20-29 years old to 56.9% for those > or =70 years old. Age-adjusted prevalence was substantially higher among non-Hispanic blacks (52.7%) and Mexican Americans (61.6%) than among non-Hispanic whites (26.2%). After controlling for age and other associated factors, the odds ratios relative to non-Hispanic whites decreased for non-Hispanic blacks, from 3.9 (95% confidence interval [CI], 3.1-4.9) to 3.3 (95% CI, 2. 6-4.2), and for Mexican Americans, from 6.3 (95% CI, 4.8-8.3) to 2.3 (95% CI, 1.6-3.5). The high prevalence of H. pylori infection among non-Hispanic blacks and Mexican Americans is partially explained by other factors associated with infection.

Association of diabetes, serum insulin, and C-peptide with gallbladder disease

An inconsistent association has been found between gallbladder disease and diabetes mellitus. We hypothesized that insulin resistance rather than diabetes status may be a primary factor involved in gallstone formation. A total of 5,653 adult participants in the third United States National Health and Nutrition Examination Survey without known diabetes underwent gallbladder ultrasonography and phlebotomy after an overnight fast for measurement of serum insulin, C-peptide, and glucose. Gallbladder disease was defined as ultrasound-documented gallstones or evidence of cholecystectomy. Subjects were characterized as having normal fasting glucose (<110 mg/dL), impaired fasting glucose (110 to <126 mg/dL), or undiagnosed diabetes (>/=126 mg/dL). After controlling for other known gallbladder disease risk factors, among women, undiagnosed diabetes was associated with increased risk of gallbladder disease (prevalence ratio [PR] = 1.91, 95% confidence interval [CI] = 1.29-2. 83); whereas impaired fasting glucose was unassociated. Gallbladder disease risk in women increased with levels of fasting insulin (PR = 1.63, 95% CI = 1.11-2.40) and C-peptide (PR = 2.07, 95% CI = 1.32-3. 25) comparing highest to lowest quintiles. However, the association of gallbladder disease with undiagnosed diabetes was not diminished when the model included fasting insulin (PR = 1.85, 95% CI = 1.24-2. 77). In men, there was a statistically nonsignificant association with undiagnosed diabetes (PR = 2.11, 95% CI = 0.76-5.85), but no association of gallbladder disease with insulin or C-peptide. Among women higher fasting serum insulin levels increased the risk of gallbladder disease, but did not account for the increased risk in persons with diabetes.

Overweight, but not high dietary fat intake, increases risk of gastroesophageal reflux disease hospitalization: the NHANES I Epidemiologic Followup Study. First National Health and Nutrition Examination Survey

PURPOSE

Gastroesophageal reflux disease is an important and increasingly common condition. Both overweight and high fat food consumption have been implicated as causes of reflux disease. We examined the relationship of overweight, high dietary fat intake, and other factors with reflux disease hospitalization.

METHODS

We studied participants in the first National Health and Nutrition Examination Survey, a population-based sample examined in 1971-75 and followed through 1992-93. Persons with a physician-diagnosed hiatal hernia at baseline or reflux disease hospitalization within the first five years of study were excluded. A second analysis included follow-up of 9851 participants free of reflux disease in 1982-84. Ninety-six percent of the baseline cohort were recontacted. Reflux disease cases were persons hospitalized with a diagnosis of esophagitis or uncomplicated hiatal hernia. Hazard rate ratios for reflux disease hospitalization according to body mass index (BMI) (kg/m2), total daily servings of high fat foods and other factors were calculated using Cox proportional hazards analysis.

RESULTS

A total of 12,349 persons were followed for a median of 18.5 years (range 5.0-22.1). Cumulative incidence of reflux disease hospitalization was 5.2% at 20 years. Multivariate survival analysis revealed higher reflux disease hospitalization rates with higher BMI (5 kg/m2) [hazard ratio (HR) = 1.22, 95% confidence interval (CI) = 1.13-1.32]. No relationship was found between higher fat intake and reflux disease hospitalization. Other factors associated with reflux disease hospitalization included age, low recreational activity, and history of doctor-diagnosed arthritis.

CONCLUSIONS

Overweight, but not high dietary fat intake, increases risk of gastroesophageal reflux disease hospitalization.

Prevalence and ethnic differences in gallbladder disease in the United States

BACKGROUND & AIMS

Gallbladder disease is one of the most common conditions in the United States, but its true prevalence is unknown. A national population-based survey was performed to determine the age, sex, and ethnic distribution of gallbladder disease in the United States.

METHODS

The third National Health and Nutrition Examination Survey (NHANES III) conducted gallbladder ultrasonography among a representative U.S. sample of more than 14, 000 persons. The diagnosis of gallbladder disease by detection of gallstones or cholecystectomy was made with excellent reproducibility.

RESULTS

An estimated 6.3 million men and 14.2 million women aged 20-74 years had gallbladder disease. Age-standardized prevalence was similar for non-Hispanic white (8. 6%) and Mexican American (8.9%) men, and both were higher than non-Hispanic black men (5.3%). These relationships persisted with multivariate adjustment. Among women, age-adjusted prevalence was highest for Mexican Americans (26.7%) followed by non-Hispanic whites (16.6%) and non-Hispanic blacks (13.9%). Among women, multivariate adjustment reduced the risk of gallbladder disease for both Mexican Americans and non-Hispanic blacks compared with non-Hispanic whites.

CONCLUSIONS

More than 20 million persons have gallbladder disease in the United States. Ethnic differences in gallbladder disease prevalence differed according to sex and were only partly explained by known risk factors.

Dietary intake and gallbladder disease: a review

OBJECTIVE

Dietary intake has long been looked upon as a potentially modifiable risk factor for gallbladder disease (GBD), here defined as either having gallstones or having had surgery for gallstones. This paper reviews the epidemiological evidence for an association between dietary intake and GBD, focusing on six dietary factors that have received the most attention in studies in this area: energy intake, fatty acids, cholesterol, carbohydrates and fibre, calcium and alcohol. The objectives of this review are to evaluate the potential usefulness of altering the diet to prevent GBD and to consider future research in this area.

DESIGN

We reviewed all English-language epidemiological studies on diet and cholelithiasis that were cross-sectional, cohort or case-control in design and that were indexed in the Medline database from 1966 to October 1997.

RESULTS

A positive association was suggested with simple sugars and inverse associations with dietary fibre and alcohol. No convincing evidence was found for a role for energy intake or intake of fat or cholesterol. Variable means of ascertaining cases and inaccurate measurement of dietary intake may contribute to variation in results across studies.

CONCLUSIONS

Some specific components of the diet that may affect GBD include simple sugars, fibre and alcohol, but whether risk for GBD can be reduced by altering intake of a specific dietary factor has not been established. Although no specific dietary recommendations can be made to reduce risk of GBD per se, a 'healthy' diet aimed at reducing risk of other diseases might be expected to reduce risk for GBD as well.

Recurrent and new hepatitis C virus infection after liver transplantation

Chronic infection with the hepatitis C virus (HCV) is the most common reason for liver transplantation. We examined the results of laboratory tests for HCV on a cohort of patients who received a liver transplant between 1990 and 1994 at three large centers. Seven hundred twenty-two recipients and 604 donors were tested for antibody to HCV (anti-HCV) using a second-generation enzyme-linked immunoassay (EIA-2), followed by recombinant immunoblot (RIBA-2) and HCV RNA confirmation by reverse-transcription polymerase chain reaction (RT-PCR) (with genotyping and viral quantification). Diagnosis of posttransplantation infection required detection of serum HCV RNA that could be genotyped by sequencing or was repeatedly positive despite being unsequenceable. Twenty-five percent of transplantation candidates were seropositive for anti-HCV. Approximately 86% of anti-HCV-positive, 93% of RIBA-positive, and 97% of HCV RNA-positive candidates developed infection after transplantation. Pretransplantation HCV RNA was superior to RIBA-2 for predicting posttransplantation infection. Whereas HCV genotype was identified in nearly all candidates and changed little after transplantation, serum viral levels rose markedly after transplantation. Fifteen donors were either anti-HCV- or HCV RNA-positive. Recipients of grafts from donors with HCV RNA all developed infection, whereas infection was not detected in recipients of grafts from donors with anti-HCV but without detectable HCV RNA. The rate of new infection fell significantly (P =.02) after the introduction of EIA-2 screening of blood. Donor and candidate markers for HCV predict posttransplantation infection.

Association of diabetes mellitus and chronic hepatitis C virus infection

While patients with liver disease are known to have a higher prevalence of glucose intolerance, preliminary studies suggest that hepatitis C virus (HCV) infection may be an additional risk factor for the development of diabetes mellitus. To further study the correlation of HCV infection and diabetes, we performed a retrospective analysis of 1,117 patients with chronic viral hepatitis and analyzed whether age, sex, race, hepatitis B virus (HBV) infection, HCV infection, and cirrhosis were independently associated with diabetes. In addition, a case-control study was conducted to determine the seroprevalence of HCV infection in a cohort of 594 diabetics and 377 clinic patients assessed for thyroid disease. In the former study after the exclusion of patients with conditions predisposing to hyperglycemia, diabetes was observed in 21% of HCV-infected patients compared with 12% of HBV-infected subjects (P =.0004). Multivariate analysis revealed that HCV infection (P =.02) and age (P =.01) were independent predictors of diabetes. In the diabetes cohort, 4.2% of patients were found to be infected with HCV compared with 1.6% of control patients (P =.02). HCV genotype 2a was observed in 29% of HCV-RNA-positive diabetic patients versus 3% of local HCV-infected controls (P <.005). In conclusion, the data suggest a relatively strong association between HCV infection and diabetes, because diabetics have an increased frequency of HCV infection, particularly with genotype 2a. Furthermore, it is possible that HCV infection may serve as an additional risk factor for the development of diabetes, beyond that attributable to chronic liver disease alone.

Genetic admixture and gallbladder disease in Mexican Americans

Gallbladder disease is a common source of morbidity in the Mexican American population. Genetic heritage has been proposed as a possible contributor, but evidence for this is limited. Because gallbladder disease has been associated with Native American heritage, genetic admixture may serve as a useful proxy for genetic susceptibility to the disease in epidemiologic studies. The objective of our study was to examine the possibility that gallbladder disease is associated with greater Native American admixture in Mexican Americans. This study used data from the Hispanic Health and Nutrition Examination Survey and was based on 1,145 Mexican Americans who underwent gallbladder ultrasonography and provided usable phenotypic information. We used the GM and KM immunoglobulin antigen system to generate estimates of admixture proportions and compared these for individuals with and without gallbladder disease. Overall, the proportionate genetic contributions from European, Native American, and African ancestries in our sample were 0.575, 0.390, and 0.035, respectively. Admixture proportions did not differ between cases and noncases: Estimates of Native American admixture for the two groups were 0.359 and 0.396, respectively, but confidence intervals for estimates overlapped. This study found no evidence for the hypothesis that greater Native American admixture proportion is associated with higher prevalence of gallbladder disease in Mexican Americans. Reasons for the finding that Native American admixture proportions did not differ between cases and noncases are discussed. Improving our understanding of the measurement, use, and limitations of genetic admixture may increase its usefulness as an epidemiologic tool as well as its potential for contributing to our understanding of disease distributions across populations.

Weight change and obesity after liver transplantation: incidence and risk factors

Obesity is a concern in the long-term management of patients following liver transplantation, yet the risk of obesity and the factors that influence its development have not been well defined. We evaluated posttransplantation weight change among a cohort of 774 adults who had their height and weight recorded before liver transplantation at three major centers. Obesity was defined as a body mass index (BMI) of at least 30 kg/m2. Weight at transplantation was adjusted by the amount of ascites removed. Mean BMI increased from 24.8 kg/m2 pretransplantation to 27.0 kg/m2 in the first posttransplantation year, to 28.1 kg/m2 in the second year, and very little with subsequent observation. Among 320 patients who were not obese before transplantation, 21.6% became obese within 2 years after transplantation. On evaluation of numerous potential donor and pretransplantation risk factors, greater recipient BMI, greater donor BMI, and being married were found to be predictors of subsequent obesity (P < .05). Posttransplantation predictors of obesity included absence of acute cellular rejection, higher cumulative prednisone dose in the second year, and cyclosporine-based immunosuppression, although only rejection and prednisone dose remained predictors on multivariate analysis. Despite the marked weight gain after transplantation, prevalence of obesity at 2 years was only slightly greater than in the general US population. Obesity occurred commonly after liver transplantation, sometimes with a striking gain in weight. In addition to BMI at transplantation, donor BMI, marital status, occurrence of acute rejection, and prednisone dose affected the incidence of obesity.

Incidence and risk factors for self-reported peptic ulcer disease in the United States

Incidence and risk factors for peptic ulcer disease in the United States have not been well defined. During the 1989 National Health Interview Survey, a population-based sample of 42,392 individuals responded to questions regarding doctor-diagnosed ulcers with confirmation by either an upper gastrointestinal series or endoscopy. Ulcers present during the previous 12 months were considered either incident ulcers if diagnosed during this period or chronic active ulcers if diagnosed more than 12 months before the interview. The incidence of ulcers over the year prior to the interview was 5.27 per 1,000 adults. Whereas incident duodenal ulcer cases represented only 2.4 percent of all persons with a history of duodenal ulcer, the corresponding value for gastric ulcer was 8.7 percent. Risk factors for incident ulcers included increasing age, lower income and educational attainment, and musculoskeletal pain or headache. These were similar to risk factors for chronic active ulcers, except smoking was an additional important risk factor for chronic active ulcers. Thus, incident peptic ulcers are common in the United States but represent a small proportion of persons with a history of ulcer disease. Smoking may be a stronger risk factor for chronic ulcers than for new ulcers.

Statistical models for predicting a beneficial response to interferon-alpha in patients with chronic hepatitis B

Therapy with interferon-alpha has been reported to induce remissions in 35% of patients with chronic hepatitis B. The ability to identify patients likely to respond would be helpful in making recommendations for treatment. In this statistical analysis we included 82 patients with chronic hepatitis B who received interferon-alpha in clinical trials at the National Institutes of Health between 1984 and 1991. A response was defined as the loss of hepatitis B virus (HBV) DNA and hepatitis B e antigen (HBeAg) within 1 year of therapy. Multiple clinical parameters measured at pretreatment (month 0) and after the first month (month 1) of therapy were selected by stepwise regression to support the development of the prognostic models: the two-stage logistic regression model and a neural network that utilized higher-order non-linear interactions between variables. Among the 82 patients, 24 (29%) were responders. The two-stage logistic model using pretreatment variables: sex, hepatic fibrosis and alanine aminotransferase (ALT) levels correctly identified 61% of responders and 76% of non-responders. When HBV DNA at month 1 along with sex, initial ALT and fibrosis was included, the resultant model correctly identified 69% of responders and 77% of non-responders. The neural network, by incorporating interactions between variables, correctly identified 77% and 86% of responders, and 87% and 92% of non-responders, using pretreatment factors alone and the combination of pretreatment and month 1 factors respectively. Hence, the neural network was more accurate than the simple logistic regression model in predicting a response to interferon-alpha in chronic hepatitis B. The universality of these models needs to be further verified.

Increased waiting time for liver transplantation results in higher mortality

BACKGROUND

Waiting time to liver transplantation (LTx) has dramatically lengthened, but the proportion of candidates who die awaiting transplantation has not increased. We evaluated whether longer waiting time for LTx candidates increases mortality.

METHODS

A cohort of candidates listed for LTx between 1990 and 1993 by three large transplantation programs was followed for 2 years. The exposure measure was ABO blood type, which is not inherently related to outcome, but is a major determinant of waiting time. The main outcome measure was 2-year mortality, as evaluated by logistic regression analysis that controlled for differences in clinical status at the time of evaluation for LTx.

RESULTS

The 308 candidates with type O blood waited longer for LTx (median 109 days) than the 399 candidates with other blood types (median 58 days) (P=0.001). Candidates listed for LTx with type O blood had better clinical status at evaluation, but then had higher pretransplantation mortality (13.3%) than other candidates (7.0%) (P=0.005). Blood group O candidates had higher 2-year mortality (26.6%) than other candidates (22.1%), which on multivariate analysis resulted in a mortality odds ratio at 2 years of 1.52 (95% confidence interval=1.04-2.23). With the difference in median waiting time between blood groups increasing from 44 days in the first year to 108 days in the third year, the 2-year mortality odds ratio also rose from 0.94 to 1.97.

CONCLUSIONS

When compared with LTx candidates with other blood types, blood type O candidates have longer waiting times and higher pretransplantation mortality, which results in higher 2-year mortality.

Transmission of hepatitis B by transplantation of livers from donors positive for antibody to hepatitis B core antigen. The National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database

BACKGROUND & AIMS

Organ donors are a potential source of transmissible disease after transplantation. The aim of this study was to evaluate the risk of acquiring hepatitis B among transplantation recipients of livers from donors without serum hepatitis B surface antigen (HBsAg) but with antibody to hepatitis B core antigen (anti-HBc).

METHODS

The transplantation experience of four centers between 1989 and 1994 was reviewed. Recipients of livers from 674 donors were considered informative for hepatitis B virus transmission.

RESULTS

Hepatitis B developed in 18 of 23 recipients of livers from anti-HBc-positive donors (78%) compared with only 3 of 651 recipients of anti-HBc-negative donor livers (0.5%) (P < 0.0001). HBsAg persisted in all recipients with donor-related hepatitis B. Liver histology showed chronic hepatitis of moderate severity in 2 of 13 recipients at 1 year and 5 of 8 recipients between 1.6 and 4.5 years from transplantation. Liver transplantation from an anti-HBc-positive donor was associated with decreased 4-year survival (adjusted mortality hazard ratio of 2.4; 95% confidence interval, 1.4-4.0).

CONCLUSIONS

De novo posttransplantation hepatitis B infection occurs at a high rate in recipients of donors with anti-HBc. Transmission of hepatitis B through transplantation suggests that the virus may persist in the liver despite serological resolution of infection.

Association between diabetes and elevated serum alanine aminotransferase activity among Mexican Americans

Elevated activities of serum aminotransferases are a common sign of liver disease and are observed more frequently among diabetics than in the general population. Whether this association is due to confounding factors is unknown. The authors investigated whether diabetes was significantly associated with elevated serum activity of alanine aminotransferase (ALT) after adjustment for factors common to both diabetes and raised ALT. Data from 2,999 men and women aged 20-74 years representative of the Mexican American population of the southwestern United States were obtained from the Hispanic Health and Nutrition Examination Survey (1982-1984). Approximately 6% of men and 2% of women had elevated serum ALT activity (>43 IU/liter). The odds ratio for diabetes as a predictor of elevated ALT was 4.1 (95% confidence interval 2.3-7.6) adjusted for age and sex, which decreased to 3.0 (95% confidence interval 0.92-9.74) after adjustment for age, sex, body mass index, alcohol consumption, and other factors. In addition to diabetes, body mass index was also significantly (p < 0.05) associated with elevated ALT activity. Heavier alcohol consumption and male sex increased the likelihood of elevated ALT, whereas coffee consumption reduced it. Diabetes and liver injury appear to be associated, even with control for factors in common.

Management of hepatitis C: a national survey of gastroenterologists and hepatologists

A survey on the management of hepatitis C virus (HCV) infection was conducted by the American Digestive Health Foundation among United States physicians who are most familiar with the disease. The two-page survey was completed by 57% of a random sample of 2,500 members of the American Gastroenterological Association and the American Association for the Study of Liver Diseases. Analysis was limited to the 1,249 responses from physicians who spent at least 1 day per week in patient care. These physicians frequently managed patients with HCV, and nearly three quarters treated patients with interferon. To prevent transmission, the large majority of physicians recommended measures to avoid blood exposures, were uncertain or disagreed about the importance of sexual contact, and did not caution patients about casual contact. More than 70% of physicians told their patients to stop or minimize alcohol consumption. In the management of a patient with antibody to HCV but normal serum aminotransferase activities, 87% of physicians would have ordered a supplemental test, and if HCV were confirmed, 46% would have obtained a liver biopsy, but only 15% would have treated the patient with interferon. For a patient with chronic HCV infection and elevated serum aminotransferase activities, more than 90% of physicians would have obtained a liver biopsy and approximately 60% would have treated with interferon. Physicians who are most familiar with the management of patients with HCV generally agreed with the recommendations of the Consensus Development Conference Panel regarding prevention of transmission, minimizing alcohol consumption, and managing patients with typical presentations. Controversies remain regarding some issues of general management, the value of molecular testing, and the need to treat certain patients with interferon.

Health impact of peptic ulcer in the United States

OBJECTIVES

To assess the general outcome and impact of current and previous peptic ulcer disease on health status in the United States.

METHODS

During the National Health Interview Survey of 1989, a special questionnaire on digestive diseases was administered to 41,457 randomly selected individuals. Various measures of impaired health in ulcer patients were expressed by their age- and sex-standardized prevalence rates.

RESULTS

Ten to 15% of all subjects with a recent ulcer reported that they had been in poor health, incapable of major activity, or unable to work for some time during the 12 months preceding the interview. Twenty to 25% of the subjects with recent ulcers complained about restricted activity and had spent 7 or more days per year in bed. About 40% of all ulcer subjects had seen a physician five or more times within 12 months before the interview. These percentages were significantly lower in patients with previous ulcer histories but no active ulcer within 12 months, but they were still significantly higher than in subjects with no ulcer history at all. In the United States, expenditures attributed to recent ulcers amounted to $5.65 billion per year.

CONCLUSIONS

In the United States, peptic ulcer disease is associated with major morbidity. Ulcer cure would result in large economic and medical savings.

The NIDDK liver transplantation database

The NIDDK Liver Transplantation Database was established to prospectively investigate questions related to the experience of patients evaluated for and undergoing liver transplantation. This article presents the study design, methods, and quality of data collection, along with some of the overall results.

METHODS

An initial 4-year planning phase was used to develop data collection instruments and quality control procedures regarding assessment for transplantation, liver donors, and the recipients' pre-, peri- and postoperative course. During the 1990-1995 implementation phase, three clinical centers refined the data collection instruments and enrolled and followed consecutive liver transplant candidates who consented to be included in the protocol.

RESULTS

The Database contains more than 49,000 data forms from 1563 candidates, 1002 donors, and 916 transplant recipients followed up to 5 years after transplantation. Overall, 95% of protocol forms were completed. The Database includes uniformly defined histology results of liver biopsies performed per protocol and for complications throughout follow-up. In addition, the Database maintains an inventory of available sera for the Serum Bank. All test results of studies performed on the sera are added to the Database. Of 1563 evaluated patients, 59% were deemed eligible for liver transplantation. Of the others who were too well or had contraindications, 15% became eligible later. Characteristics of patients in this study were generally comparable to those of patients nationally.

CONCLUSIONS

The NIDDK Liver Transplantation Database has yielded comprehensive and high quality data and is a rich resource for extensive analysis about many important clinical aspects of liver transplantation.

Correlations with self-reported weight loss in overweight U.S. adults

The authors investigated two issues among overweight men and women in the U.S.: 1) what is the influence of the self-expressed intention to lose weight in the presence of other potential predictors of loss and 2) what are easily identifiable predictors of intentional weight loss during a 1-year recall period. The sample consisted of 1996 overweight men (body mass index (BMI > or = 27.8 kg/m2) and 2586 overweight women (BMI > or = 27.3 kg/m2) who answered questions regarding 1-year weight change in a Current Health Topic supplement of the population-based 1989 National Health Interview Survey. Of these overweight persons, 56.8% of men and 72.1% of women attempted to lose weight during the previous year. The most important characteristic associated with weight loss was the expressed intention itself. For any weight loss, the odds ratios (95% confidence intervals) for intention were 4.6 (3.6-5.9) for men and 3.8 (2.8-5.0) for women. Controlling for other factors reduced the odds only slightly, to 4.3 for men and 3.5 for women. Among women, older age, having a greater frequency of blood pressure checks, and being in poorer health reduced the influence of intent as a predictor of loss. To address the second objective, the identification of predictors of intentional 1-year weight loss, analysis was restricted to overweight persons who attempted to lose weight. For both sexes, statistically significant predictors (p < 0.05) included never being married, smoking, higher BMI, being diabetic, and having a higher number of blood pressure checks. Being divorced or separated was predictive of weight loss in men only. Also, men were more likely to achieve weight loss than women. In conclusion, 1-year weight loss among the overweight was primarily a function of the intention to lose weight, although other factors contributed to determine whether weight loss was achieved.

The prevalence of self-reported peptic ulcer in the United States

OBJECTIVES

The purpose of this study was to draw a current picture of the sociodemographic characteristics of peptic ulcer in the United States.

METHODS

During the National Health Interview Survey of 1989, a special questionnaire on digestive diseases was administered to 41,457 randomly selected individuals. Data were retrieved from public use tapes provided by the National Center for Health Statistics. Odds ratios were calculated by logistic regression after adjustment for sample weights in the survey.

RESULTS

Of adult US residents, 10% reported having physician-diagnosed ulcer disease, and one third of these individuals reported having an ulcer in the past year. Old age, short education, low family income, being a veteran, and smoking acted as significant and independent risk factors. Gastric and duodenal ulcer occurred in both sexes equally often. Duodenal ulcer was more common in Whites than non-Whites, while gastric ulcer was more common in non-Whites.

CONCLUSIONS

The age-related rise and socioeconomic gradients of peptic ulcer represent the historic scars of previous infection rates with Helicobacter pylori. The racial variations reflect different ages at the time of first infection; younger and older age at the acquisition of H. pylori appear to be associated with gastric and duodenal ulcer, respectively.

Unintentional weight loss in the United States

Lower weight is usually considered advantageous to health, yet weight loss has been associated with increased mortality. An explanation for this paradox might be that the benefits of weight loss may depend on whether the loss is intentional or unintentional. The authors investigated whether intentional and unintentional weight loss differed in their associations with known risk factors for morbidity and mortality in a nationally representative sample of the US population. The sample consisted of 9,144 persons, aged 45 years and older, who answered questions regarding 1-year weight change in the diabetes risk factor Current Health Topic of the 1989 National Health Interview Survey (NHIS). Statistical analyses incorporated the sample weights and characteristics of the survey design. Relative to a common referent group, the factors associated with weight loss differed depending on whether the loss was defined as intentional loss, as unintentional loss, or regardless of intention. Restricting analysis to the 1,999 persons who lost weight, unintentional relative to intentional weight loss was significantly (p < 0.05) associated with older age, poorer health status, smoking, lower body mass index, and, in men only, widowhood and less education. Thus, unintentional weight loss may serve as a marker for factors that characterize persons at greater risk of mortality than persons undergoing intentional weight loss. Also, intention to lose weight may help clarify the relation between weight loss and mortality that, to this point, has shown counterintuitive results. Studies of the relation between weight loss and mortality should incorporate intention as a factor in the analysis.

Self-reported substantial 1-year weight change among men and women in the United States

Population-based data have not been readily available on relatively short-term changes in weight. Therefore, we sought to determine the nature of self-reported substantial (> 10%) weight change over one year in a representative sample of the US population which participated in the 1989 National Health Interview Survey (NHIS). Across all ages, a larger proportion of women than men reported both weight loss as well as weight gain of any amount (18.9% vs. 16.1% for weight loss and 20.0% vs. 16.1% for weight gain). In sex-specific logistic regression analyses, significant risk factors common to both sexes for substantial weight loss included divorced/separated marital status, smoking, increased number of blood pressure checks, increased BMI (body mass index) and increased number of bed days. Black race reduced the risk of weight loss for both men and women. Sex-specific risk factors for weight loss in men only were widowhood or never married marital status, while increasing age was a protective factor in women only. Concerning weight gain > 10% over the past year, increased number of blood pressure checks and having one or more diabetic parents were significant risk factors among both men and women; while never being married, increased age, BMI, and education exerted a protective effect in both sexes. For women only, risk factors for weight gain included black race, increased number of contacts with a health professional, and being unemployed. Intention to lose weight was associated with both weight gain and weight loss in both sexes, although it did not serve as a confounder in any of these relationships. A greater likelihood of substantial weight loss among women relative to men was diminished for persons with higher BMI, higher number of blood pressure checks, being widowed, divorced or separated, and intention to lose weight. A greater likelihood of substantial weight gain among women relative to men was diminished for persons with low BMI. The results of this cross-sectional study of weight change, involving a one-year follow-up period, generally correspond with the results obtained by longitudinal studies involving a longer follow-up.

Growth and body mass index of Brazilians ages 9 through 17 years

Obesity during adolescence is considered a strong predictor of adult obesity, and obesity and overweight have been increasing among Brazilian adults. To gauge the relative frequency of overweight among adolescents in Brazil, we compared the distributions of body mass index (kg/m2) and stature in national population based samples of the U.S. and Brazil. U.S. adolescents were on average about 10 cm taller than Brazilians, although growth spurts occurred at the same age for both populations. Brazilian adolescents were leaner than their U.S. counterparts. This difference was reduced among girls in the postpubertal period. At age 17 years, U.S. boys were about 10 kg heavier than Brazilian boys, but the difference among girls was only 2 kg. In families above the poverty level in the more developed South region, body mass index distribution for boys was closer to that of the U.S., and older girls tended to have higher body mass index than U.S. girls. Within Brazil, body mass index varied by ethnicity with Mulattos, but not Blacks, of both sexes having lower body mass index than Whites of the same age. Urban adolescents had higher body mass index than those living in rural areas. In general, the patterns seen among Brazilian adults were found among children. Among girls, in particular, overweight has become an identifiable problem during adolescence.

High temporal, geographic, and income variation in body mass index among adults in Brazil

OBJECTIVES

Population-based data on body mass index for developing countries are scarce. Body mass index data from two Brazilian surveys were examined to determine regional and temporal variations in the prevalences of underweight, overweight, and obesity.

METHODS

Nationwide surveys in 1974/75 and 1989 collected anthropometric data in Brazil from 55,000 and 14,455 households, respectively. Trained interviewers used the same methods to measure weight and stature in both surveys, and survey designs were identical. Prevalences of underweight, overweight, and obesity were determined for persons 18 years of age and older.

RESULTS

In the 1989 survey, body mass index varied greatly according to region of the country, urbanization, and income. In the wealthier South, the prevalence of overweight/obesity was the highest and the prevalence of underweight was the lowest; in the poorer rural Northeast, these patterns were reversed. For both surveys, overweight/obesity was more common among women than among men and peaked at age 45 to 64 years in both sexes. Over the 15 years between surveys, the prevalence of both overweight and obesity increased strikingly.

CONCLUSIONS

In contrast to findings in developed countries, obesity in Brazil was positively associated with income and was much more prevalent among women than among men. For Brazilian women, the overall prevalence of overweight was nearly as high as that among women in the United States.

Contributions of obesity and weight loss to gallstone disease

OBJECTIVE

To examine the relation of obesity and weight loss to the formation of gallstones according to pertinent clinical and research issues.

DATA SOURCES AND EXTRACTION

Original reports obtained through a MEDLINE search from 1966 to 1992 on gallstones plus obesity or reducing diets, supplemented by a manual search of bibliographies, a Current Contents title search from 1991 to 1992 on gallstones and gallbladder, and expert opinion. Only studies of humans were cited.

DATA SYNTHESIS

For women, but less so for men, obesity is a strong risk factor for gallstones, and this risk is increased during weight loss. Between 10% and 25% of obese men and women may develop gallstones within a few months of beginning a very low calorie diet, and perhaps one third of these will develop symptoms of gallstones. Persons with the highest body mass index before weight loss and those who lose weight most rapidly appear to be at the greatest risk for gallstones. Treatment with ursodeoxycholic acid (ursodiol) during weight loss dieting is the only proven prevention for the formation of gallstones. Issues to be resolved include how different diets affect the risk for developing gallstones, the identification of other risk factors for gallstone formation during weight loss, the effect of weight loss among people with preexisting gallstones, and the optimum means of preventing gallstones during weight loss.

CONCLUSIONS

During weight loss, particularly among the obese, an increased risk exists for symptomatic gallstone formation. This acute risk offers the opportunity to investigate the cause of gallstones and possibly to prevent them.

Geographical patterns of proportionate mortality for the most common causes of death in Brazil

Mortality due to chronic diseases has been increasing in all regions of Brazil with corresponding decreases in mortality from infectious diseases. The geographical variation in proportionate mortality for chronic diseases for 17 Brazilian state capitals for the year 1985 and their association with socio-economic variables and infectious disease was studied. Calculations were made of correlation coefficients of proportionate mortality for adults of 30 years or above due to ischaemic heart disease, stroke and cancer of the lung, the breast and stomach with 3 socio-economic variables, race, and mortality due to infectious disease. Linear regression analysis included as independent variables the % of illiteracy, % of whites, % of houses with piped water, mean income, age group, sex, and % of deaths caused by infectious disease. The dependent variables were the % of deaths due to each one of the chronic diseases studied by age-sex group. Chronic diseases were an important cause of death in all regions of Brazil. Ischaemic heart diseases, stroke and malignant neoplasms accounted for more than 34% of the mortality in each of the 17 capitals studied. Proportionate cause-specific mortality varied markedly among state capitals. Ranges were 6.3-19.5% for ischaemic heart diseases, 8.3-25.4% for stroke, 2.3-10.4% for infections and 12.2-21.5% for malignant neoplasm. Infectious disease mortality had the highest (p < 0.001) correlation with all the four socio-economic variables studied and ischaemic heart disease showed the second highest correlation (p < 0.05). Higher socio-economic level was related to a lower % of infectious diseases and a higher % of ischaemic heart diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Relative weight classifications in the assessment of underweight and overweight in the United States

We compared five recent relative weight classifications based on body mass index for their estimates of prevalence of underweight and overweight in the adult population of the United States and for their ability to predict subsequent morbidity and mortality. The sources of the classifications were: the 1990 Dietary Guidelines for Americans of the US Departments of Agriculture and Health and Human Services, the National Academy of Sciences, the National Center for Health Statistics, the World Health Organization, and the Canadian Minister of National Health and Welfare. These classifications were applied to the body mass index distributions of the second National Health and Nutrition Examination Survey (1976-1980) and to the Hispanic Health and Nutrition Examination Survey (1982-1984). Depending on classification, a wide range of prevalence for the total population was found: 9-17% of the US population were categorized as underweight, and 25-45% were categorized as overweight. White women had the highest prevalence of underweight in all but the National Center for Health Statistics classification. Black and Mexican American women had the highest prevalence of overweight under all classifications (range: 38.4-58.6%). Associations with health outcomes were determined using all cause hospitalization and mortality in the 1971-1987 follow-up of the first National Health and Nutrition Examination Survey. Underweight and overweight as defined by the National Academy of Sciences classification had the highest population attributable risk for hospitalization and death: 5.0% of hospitalizations and 11.0% of deaths among men and 4.2% of hospitalizations and 11.4% of deaths among women were associated with weights outside the healthy range. Under this classification a greater proportion of both hospitalizations and mortality were associated with overweight than underweight. For all classifications, a higher proportion of hospitalizations were associated with overweight than underweight. All classifications performed better at predicting death than hospitalization.

Duration of obesity increases the incidence of NIDDM

The effect of duration of obesity on incidence of non-insulin-dependent diabetes mellitus (NIDDM) was determined among Pima Indians. Duration of obesity was defined as the time since body mass index (BMI) was first known to be at least 30 kg/m2. Among 1057 participants eligible for study, there were 224 incident cases of NIDDM in 5975 person-yr of follow-up. The association of duration of obesity with incidence of diabetes adjusted for age, sex, and current BMI was highly significant (P less than 0.0001). This adjusted incidence of diabetes in cases/1000 person-yr of obesity was 24.8 for people with less less than 5 yr of obesity, 35.2 for people with 5-10 yr of obesity, and 59.8 for people with at least 10 yr of obesity. There was no apparent excess risk of diabetes for people who had a BMI of at least 30 kg/m2 and then lost weight. They had a slightly nonsignificantly higher rate than people who had not attained a BMI of at least 30 kg/m2 and a lower rate than people whose BMI remained 30-35 kg/m2. The relationship of duration of obesity with serum insulin concentrations among nondiabetic people was determined controlling for sex and age, BMI, and plasma glucose concentrations at the time of a glucose tolerance test. Duration of obesity was inversely associated with fasting serum insulin concentration through most of the range of fasting plasma glucose concentrations (P less than 0.001) and tended to be inversely associated with 2-h postload serum insulin concentration through the entire range of postload plasma glucose concentrations (P = 0.058).

A prospective study of hospitalization with gallstone disease among women: role of dietary factors, fasting period, and dieting

BACKGROUND

Dietary risk factors for the development of gallstones have not been clearly established. We analyzed data from a population-based prospective study to determine dietary risk factors for hospitalization with gallstone disease.

METHODS

We evaluated the role of dietary constituents, fasting, and dieting on subsequent hospitalization with gallstone disease among 4,730 women, ages 25 to 74 years, who participated in the first follow-up of the first National Health and Nutrition Examination Survey. Baseline dietary variables were established through a 24-hour dietary recall and a medical history. Proportional hazards models were used to calculate the effects of dietary variables while controlling for baseline risk factors.

RESULTS

After an average of 10 years follow-up, gallstone disease was confirmed by hospital records among 216 women who denied gallstone disease at the baseline examination. The hazard rate of hospitalization with gallstone disease increased with increasing overnight fasting period and with dieting. Intake of fiber showed a small protective effect. The effect of energy intake was significant only among women younger than age 50 years at baseline. Results were not affected by adjustment for known risk factors for gallstone disease or other dietary factors.

CONCLUSION

A long overnight fasting period, dieting, and low fiber intake may increase the risk of hospitalization with gallstone disease.

Long-term remission of chronic hepatitis B after alpha-interferon therapy

OBJECTIVE

To evaluate whether remissions of chronic hepatitis B induced by alpha-interferon therapy are of long duration.

DESIGN

Cohort study.

SETTING

Clinical Center of the National Institutes of Health, a tertiary referral center.

PATIENTS

Sixty-four patients with chronic hepatitis B were treated with alpha-interferon between 1984 and 1986.

MAIN OUTCOME MEASURES

Patients were followed with frequent examinations and determinations of serum liver biochemical tests and hepatitis B virus (HBV) markers including hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and HBV DNA using blot hybridization and polymerase chain reaction.

RESULTS

Among 64 patients with chronic hepatitis B who were treated with alpha-interferon, 23 (36%) responded to treatment with loss of HBeAg and improvement in serum aminotransferases. All 23 have been followed for 3 to 7 years (mean, 4.3 years). During follow-up, 3 of 23 patients relapsed, with reappearance of HBeAg and abnormal serum aminotransferases, all within 1 year of therapy. The remaining 20 patients continued to have no detectable HBeAg or HBV DNA (using blot hybridization) in serum and to be asymptomatic for liver disease, although 3 had minimal elevations in serum aminotransferases. Thirteen patients (65%) became negative for HBsAg between 0.2 and 6 years (mean, 3 years) after loss of HBeAg. Although no patient had HBV DNA that was detectable by blot hybridization, the 7 patients who remained HBsAg positive all had HBV DNA in serum detected by polymerase chain reaction, but only 2 of 13 HBsAg-negative patients had viral genome using this method. Testing sequential samples indicated that HBV DNA detected by polymerase chain reaction usually disappeared at or around the time that test results for HBsAg became negative.

CONCLUSIONS

Remissions in chronic hepatitis B induced by alpha-interferon are of long duration and are followed, in most patients, by the loss of HBsAg and all evidence of residual virus replication.