The association of variants in the FTO gene with longitudinal body mass index profiles in non-Hispanic white children and adolescents.

OBJECTIVE: To investigate possible age-related changes in associations between polymorphisms in the fat mass and obesity-associated (FTO) gene and higher body mass index (BMI). DESIGN AND SUBJECTS: Multilevel mixed regression models were used to examine associations between four FTO variants and longitudinal BMI profiles in non-Hispanic white and African American children and adolescents 8-17 years of age from two different longitudinal cohort studies, the Bogalusa Heart Study (BHS) and Project HeartBeat! (PHB). In the BHS, there were 1551 examinations of 478 African Americans and 3210 examinations of 1081 non-Hispanic whites; in PHB, there were 971 examinations of 131 African Americans and 4458 examinations of 505 non-Hispanic whites. RESULTS: In African Americans, no significant FTO associations with BMI were found. In non-Hispanic whites, linkage disequilibrium among all four variants made haplotype analysis superfluous, so we focused on the single-nucleotide polymorphism, rs9939609. In longitudinal multilevel models, the A/A genotype of rs9939609 was associated with higher BMI in non-Hispanic whites in both cohorts at all ages. A significant age-by-genotype interaction found only in the BHS cohort predicted that in those with the A/A genotype, BMI would be ∼0.7 kg m(-2) higher at age 8 and ∼1.6 kg m(-2) higher at age 17 than in those with A/T or T/T genotypes. The design of PHB limited follow-up of any single individual to 4 years, and may have reduced the ability to detect any age-by-genotype interaction in this cohort. CONCLUSIONS: The A/A genotype of rs9939609 in the FTO gene is associated with higher longitudinal BMI profiles in non-Hispanic whites from two different cohorts. The association may change with age, with the A/A genotype being associated with a larger BMI difference in late adolescence than in childhood, though this was observed only in the BHS cohort and requires verification.

Change in level of physical activity and risk of all-cause mortality or reinfarction: The Corpus Christi Heart Project.

BACKGROUND: The role of physical activity (PA) in reducing the risk of all-cause mortality or reinfarction after a first myocardial infarction (MI) remains unresolved, particularly for minority populations. The association between change in level of PA and risk of death or reinfarction was studied in 406 Mexican American and non-Hispanic white women and men who survived a first MI. METHODS AND RESULTS: MI patients were interviewed at baseline and annually thereafter about PA, medical history, and risk factors of coronary heart disease. Change in level of PA after the index MI was categorized as (1) sedentary, no change (referent group), (2) decreased activity, (3) increased activity, and (4) active, no change. Over a 7-year period, the relative risk (95% CI) of death was as follows: 0.21 (0.10 to 0.44) for the active, no change group; 0.11 (0.03 to 0.46) for the increased activity group; and 0.49 (0.26 to 0.90) for the decreased activity group. The relative risk of reinfarction was as follows: 0.40 (0.24 to 0.66) for the active, no change group; 0.22 (0.09 to 0.50) for the increased activity group; and 0.93 (0.59 to 1.42) for the decreased activity group. CONCLUSIONS: These findings are consistent with a beneficial role of PA for Mexican American and non-Hispanic white women and men who survive a first MI and have practical implications for the management of MI survivors.

The relation of diabetes to the severity of acute myocardial infarction and post-myocardial infarction survival in Mexican-Americans and non-Hispanic whites. The Corpus Christi Heart Project.

The effect of diabetes on survival after myocardial infarction (MI) was examined in a prospective population-based study of individuals hospitalized with MI in a bi-ethnic community of Mexican-Americans and non-Hispanic whites. Among Mexican-Americans, 54% (331 of 610) had diabetes compared with 33% (192 of 589) of non-Hispanic whites (P < 0.001). Among those with diabetes, the prevalence of a history of a cardiac event before the index admission was significantly higher (odds ratio = 1.4, 95% confidence interval [CI] 1.1-1.8) than among nondiabetic subjects. During the index hospitalization, diabetic subjects received cardiac catheterization less frequently than did nondiabetic subjects (45.1 vs. 51.5%, P = 0.03). Diabetic subjects had lower estimated ejection fractions, and the number of coronary arteries with significant obstruction (> 75%) was higher (P < 0.001). The peak creatine phosphokinase and creatine phosphokinase myocardial isoenzyme (CK-MB) levels were similar in diabetic and nondiabetic subjects. Despite a similar infarct size, diabetic subjects had a higher incidence of congestive heart failure (relative ratio = 2.2, 95% CI 1.7-2.8), more adverse indexes of short-term and long-term prognosis, and a longer average hospital stay (12.1 vs. 8.9 days, P < 0.01). After adjustment for age, sex, and ethnicity, the cumulative risk for total mortality, over 44 months of follow-up, was 37.4% among diabetic compared with 23.3% among nondiabetic subjects (P < 0.001). Diabetic subjects had a higher 28-day case-fatality rate post-MI as well as higher long-term mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence of intraprison spread of HIV infection.

BACKGROUND: Individuals entering prison are known to have high rates of human immunodeficiency virus (HIV) infection, and inmates are known to engage in high-risk behavior. This suggests the potential for intraprison spread of HIV infection, but this has not been documented. METHODS: All prisoners (N = 556) in the Florida Department of Corrections who had been continuously incarcerated since 1977 were identified. The medical records of these prisoners were reviewed to determine whether they had been tested for HIV infection and, if tested, whether the results were positive. Results were considered positive if there were reactions to two enzyme-linked immunosorbent assays confirmed by Western blot assay. If an individual tested positive, the medical record was reviewed to determine whether the patient had been treated for conditions consistent with HIV infection. RESULTS: Eighty-seven of the 556 prisoners had undergone testing for HIV infection. Of the tested inmates, 18 (21%) were found to be positive for HIV infection. Eight of these individuals had no HIV-related conditions, and 10 had HIV-related symptoms. CONCLUSIONS: The results present strong evidence for intraprison transmission of HIV infection. Given that most inmates serve relatively short sentences, there is a strong possibility that prison-acquired HIV infection will be carried into the "free world." Preventive programs in prisons may be very important in controlling HIV infection in our society.

Pediatric blood pressure: ethnic comparisons in a primary care center.

This study reviews the blood pressure (BP) determinations previously recorded in a primary care center serving a low socioeconomic population and compares the systolic blood pressure (SBP) and diastolic blood pressure (DBP) distributions within the clinic population among the three major ethnic groups represented, and also between this clinic population and a recently reported standard population (Task Force for Blood Pressure Control in Children, NHLBI). The study group consisted of 2810 children 3-17 years of age, of whom 49.2% were of Spanish surname, 23.4% black, and 27.4% white. As a standard clinic procedure, BP readings were obtained from the right arm with the subject seated. Comparisons of the average SBP by 3-year age groups, by sex, within the clinic population showed that blacks had higher SBPs than children with Spanish surnames or whites in all of the five male subgroups and in four of the five female subgroups. Black males had higher DBPs than Spanish or whites in four of the five subgroups; black females had higher DBPs in three of the five subgroups. In comparison with the standard population, the overall 95th percentile values for both SBP and DBP were lower. The prevalence of readings above the 95th percentile values reported for the standard population over all age groups was as follows: SBP, 1.53%; DBP, 1.60%; and both SBP and DBP, 0.57%. Proportionately, elevated readings were most common among blacks and least common among whites. However, these differences between ethnic groups could be accounted for statistically, to a great extent, by adjusting for height and weight, since blacks were the tallest and heaviest of the three groups. These results suggest that, even in childhood, blacks presenting at a primary care center have higher BPs than Spanish or whites, but that this differences is largely related to body size.

Rise of blood pressure with age. New evidence of population differences.

Epstein and Eckoff in 1967 devised a scheme to summarize population differences in the rise of mean values of systolic blood pressure by age in accordance with their slopes and levels. For the first time, the validity of this scheme can be examined with data from a single study, INTERSALT. This study included 52 populations in 32 countries. On the basis of these data, collected in an exceptionally well-standardized mode under a common protocol, the diversity of populations in the slopes of age differences in median values of systolic blood pressure has been strongly reconfirmed. Populations with no increase in median systolic blood pressure were again observed and remained exceptional. The analyses of these data also indicate a positive relation between the slope of rising systolic blood pressure with age and urinary sodium, urinary sodium-potassium ratio, and reported alcohol consumption as well as a negative association between urinary potassium excretion and blood pressure slope. The present analyses therefore add to the previous knowledge and results published by the INTERSALT investigators in the following three respects: (1) they relate INTERSALT results to the postulated biological gradient of variation among populations as presented by Epstein and Eckoff, including explanatory variables; (2) they demonstrate strong correlation between ranks of median blood pressure at 40 to 49 years and values at 20 to 29 years; and (3) they therefore support the original Epstein and Eckoff concept of population variation, link this with blood pressure risk factors, and call attention to the large degree of population differences already evident among populations at 20 to 29 years of age.

Reserpine and breast cancer in the Hypertension Detection and Follow-Up Program.

Recent reports on the efficacy of pharmacological management in reducing mortality associated with mild hypertension have enhanced the importance of increasing our knowledge about drug toxicity. The Hypertension Detection and Follow-Up Program (HDFP) provides a convenient setting in which to examine the association reported between reserpine usage and breast cancer. In the intensively treated and followed group (Stepped Care [SC]), the relative breast cancer experience of those who did take reserpine and those who did not was examined. Of 2529 females in SC, 1036 received reserpine, with an average exposure of 1.97 years during 5 years of follow-up. Through extensive investigation, 21 cases of breast cancer were identified. using a life table regression method of analysis to adjust for actual time of reserpine exposure, race, sex, and medication status at entry, and comparing those who took reserpine with those who did not, the author's calculated a risk ratio of 1.28, with a confidence interval of 0.58 to 2.80. Adjustment for a number of other variables known to have relationships to breast cancer did not appreciably change the results. Thus, with certain precautions, the authors conclude that in this setting there is no indication of the recently postulated association of reserpine and the short-term enhancement of breast tumor growth.

Validity of echocardiographic measurement in an epidemiological study. Project HeartBeat!

In Project HeartBeat!, a longitudinal study of cardiovascular disease risk factors in healthy children and adolescents, 3 samples of 40, 80, and 182 echocardiograms, respectively, were randomly selected and reread to evaluate intraobserver and interobserver variabilities and comparability between measurements of field echocardiographic technicians and reference readings at Texas Children's Hospital. Included in the evaluation were 8 M-mode echocardiographic measurements, ie, aortic root diameter, left atrial diameter, and end-diastolic and end-systolic measurements of interventricular septal thickness, left ventricular (LV) diameter, and LV posterior wall thickness; 8 Doppler measurements; and a calculated LV mass. Means and SDs of the differences of the paired measurements were used to assess the relative bias and random error of the measurements. For the intraobserver comparison, means and SDs of the differences were very small, indicating that the echo measurements were performed consistently by each project echo technician. Interobserver comparison showed statistically but not clinically significant differences between the paired readings of end-diastolic septal thickness, end-systolic LV posterior wall thickness, and 5 Doppler measurements. Comparison with reference readings at Texas Children's Hospital showed significant differences in diastolic LV diameter, systolic septal thickness, and right ventricular ejection time. These differences, however, were minimal with limited clinical significance. Mean differences in LV mass for the corresponding comparisons were -1.82, 4.50, and 0.0013 g, and the SDs were 18.79, 24.16, and 12.35 g, respectively. We conclude that the echocardiographic measurements taken from healthy children in a longitudinal study can be made accurately with acceptable reproducibility.

Training and certification of blood pressure observers.

Accurate, reproducible measurements of blood pressure (BP) were central to the goals and objectives of the Hypertension Detection and Follow-Up Program (HDFP), a multicenter clinical trial on the efficacy of pharmacological treatment of individuals with elevated BP. All potential BP observers with or without previous experience in measuring BP were required to undergo a defined training program and meet set performance criteria to be certified to take HDFP BP. Recertification was required twice a year. Originally an audiotape test was used to measure accuracy of BP readings. This approach was later replaced by a videotape test, which proved more realistic and an equally effective tool for long-term quality control. With this technique of certifications, 75% of the individuals taking the test passed on the first attempt and more than 95% passed with one or two attempts. Although agreement for blinded BP duplicates was generally good, the appearance of sound (systolic BP) was identified with greater reproducibility than was the disappearance (diastolic BP). These recertification procedures were of great value in assuring the continued high quality of our BP data.

Prevalence of hypertension in the US adult population. Results from the Third National Health and Nutrition Examination Survey, 1988-1991.

The purpose of this study was to estimate the current prevalence and distribution of hypertension and to determine the status of hypertension awareness, treatment, and control in the US adult population. The study used a cross-sectional survey of the civilian, noninstitutionalized population of the United States, including an in-home interview and a clinic examination, each of which included measurement of blood pressure. Data for 9901 participants 18 years of age and older from phase 1 of the third National Health and Nutrition Examination Survey, collected from 1988 through 1991, were used. Twenty-four percent of the US adult population representing 43,186,000 persons had hypertension. The age-adjusted prevalence in the non-Hispanic black, non-Hispanic white, and Mexican American populations was 32.4%, 23.3%, and 22.6%, respectively. Overall, two thirds of the population with hypertension were aware of their diagnosis (69%), and a majority were taking prescribed medication (53%). Only one third of Mexican Americans with hypertension were being treated (35%), and only 14% achieved control in contrast to 25% and 24% of the non-Hispanic black and non-Hispanic white populations with hypertension, respectively. Almost 13 million adults classified as being normotensive reported being told on one or more occasions that they had hypertension; 51% of this group reported current adherence to lifestyle changes to control their hypertension. Hypertension continues to be a common finding in the general population. Awareness, treatment, and control of hypertension have improved substantially since the 1976-1980 National Health and Nutrition Examination Survey but continue to be suboptimal, especially in Mexican Americans.(ABSTRACT TRUNCATED AT 250 WORDS)

Trends in the prevalence, awareness, treatment, and control of hypertension in the adult US population. Data from the health examination surveys, 1960 to 1991.

The objective of this study was to describe secular trends in the distribution of blood pressure and prevalence of hypertension in US adults and changes in rates of awareness, treatment, and control of hypertension. The study design comprised nationally representative cross-sectional surveys with both an in-person interview and a medical examination that included blood pressure measurement. Between 6530 and 13,645 adults, aged 18 through 74 years, were examined in each of four separate national surveys during 1960-1962, 1971-1974, 1976-1980, and 1988-1991. Protocols for blood pressure measurement varied significantly across the surveys and are presented in detail. Between the first (1971-1974) and second (1976-1980) National Health and Nutrition Examination Surveys (NHANES I and NHANES II, respectively), age-adjusted prevalence of hypertension at > or = 160/95 mm Hg remained stable at approximately 20%. In NHANES III (1988-1991), it was 14.2%. Age-adjusted prevalence at > or = 140/90 mm Hg peaked at 36.3% in NHANES I and declined to 20.4% in NHANES III. Age-specific prevalence rates have decreased for every age-sex-race subgroup except for black men aged 50 and older. Age-adjusted mean systolic pressures declined progressively from 131 mm Hg at the NHANES I examination to 119 mm Hg at the NHANES III examination. The mean systolic and diastolic pressures of every sex-race subgroup declined between NHANES II and III (3 to 6 mm Hg systolic, 6 to 9 mm Hg diastolic). During the interval between NHANES II and III, the threshold for defining hypertension was changed from 160/95 to 140/90 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of stroke hospitalization rates among Mexican-Americans and non-Hispanic whites.

The authors performed a prospective, community-based pilot stroke surveillance project in Nueces County, TX. Mexican-Americans showed a trend toward higher completed ischemic stroke hospitalization rates compared with non-Hispanic whites. Mexican-Americans were more commonly uninsured (p = 0.007) and were less likely to receive neuroimaging (p = 0.001). Additional studies are needed to confirm this finding and to determine the role of stroke risk factors and access to care variables.

Community-wide coronary heart disease mortality in Mexican Americans equals or exceeds that in non-Hispanic whites: the Corpus Christi Heart Project.

PURPOSE: Previous comparisons of coronary heart disease mortality between Mexican Americans and non-Hispanic whites have given paradoxic results: despite their adverse cardiovascular risk profiles, especially a greater prevalence of diabetes, Mexican Americans are reported to have lower rates of mortality from coronary heart disease. SUBJECTS AND METHODS: We performed a community-based surveillance among all residents of Nueces County, Texas, aged 25 to 74 years, from 1990 to 1994. All death certificates were obtained and coded, and deaths potentially related to coronary heart disease were selected and validated by standardized methods blinded to ethnicity. Validated in-hospital and out-of-hospital coronary heart disease mortality was compared between 785 Mexican Americans and 862 non-Hispanic white women and men. RESULTS: Validated coronary heart disease mortality in Mexican Americans exceeded that for non-Hispanic whites in the same community. Among women, definite coronary heart disease mortality was 40% greater among Mexican Americans (rate ratio [RR] 1.43, 95% confidence interval [CI]: 1.12 to 1.82), as was all coronary heart disease mortality (RR, 1.32, 95% CI: 1.08 to 1.63). Among men, Mexican Americans had greater rates of all (RR, 1.11; 95% CI: 0.96 to 1.28) and definite coronary heart disease mortality (RR, 1.16; 95% CI: 0.91 to 1.47), but the associations were not statistically significant. CONCLUSIONS: When community-wide mortality rates from coronary heart disease are properly validated, Mexican Americans have rates equal to or higher than those of non-Hispanic whites. Community-based surveillance with validation of coronary heart disease as the cause of death is necessary to avoid the errors that occur with the use of death certificates alone.

Intake and food sources of dietary fat among schoolchildren in The Woodlands, Texas.

To investigate the nutrient intake and food use patterns among schoolchildren, diet was assessed among 138 children and adolescents in grades 5 through 12 using three random, nonconsecutive, 1-day food records. Mean intake of total fat, saturated fat, and polyunsaturated fat as percent of calories was 35.6%, 13.4%, and 6.6%, respectively. Among all subjects, 17% consumed diets containing less than 30% of calories from fat, 34% consumed greater than or equal to 38% of calories from fat, 7% consumed less than 10% of calories from saturated fatty acids, and greater than 97% ate less than 300 mg of cholesterol per day. While intake of calories, sodium, and beta-carotene per 1000 kcal was higher in subjects consuming higher fat diets, intake of other micronutrients was either higher among those eating low-fat diets or did not differ by level of fat intake. Differences were seen in the amount of saturated fat and cholesterol that individual food sources contributed to the diets of subjects eating high and low fat diets. These cross-sectional data show that a substantial proportion of children and adolescents in this population are consuming diets low in fat and cholesterol without systematic differences in intake of other nutrients, suggesting that current dietary guidelines regarding fat intake are attainable within the current food use pattern of healthy, school-aged children and adolescents.

Cholesterol screening in pediatric practice.

Four pediatricians introduced a portable cholesterol analyzer into their group practice. Their experience is described on the basis of 12 months of screening in 1665 children and adolescents. The overall 50th and 90th percentile values for a subgroup of 1406 routinely screened children were 156 and 197 mg/dL, respectively, but there was marked variation in these values among specific age and sex groups. Cholesterol levels decreased by age group during the early teenage years and increased thereafter, these changes occurring at ages approximately 2 years younger for girls than for boys. Further analysis of screening results for 398 sibling pairs demonstrated significant concordance between paired cholesterol levels when classified by the respective age- and sex-specific 90th percentile values for each member of the pair. Sibling pairs in which both members' cholesterol values exceeded their 90th percentile value were identified 2.4 times as frequently as expected (confidence interval 1.1 to 4.5, P = .029). The observations reported here indicate that office-based cholesterol screening in a pediatric practice may be both practical and useful, although further consideration of screening criteria is needed. Age- and sex-specific reference values for cholesterol levels during childhood could improve screening results. Special emphasis should be directed toward screening siblings of children in whom high cholesterol levels have been detected.

The prevalence of hypertension in the United States today.

The simplest response to the question, what is the prevalence of hypertension in the United States today?, is given by a currently popular slogan: 23,000,000 Americans have hypertension. It is clear that the problem is large in scale, but this figure alone is an insufficient guide to many practical issues. The prevalence ratio underlying this estimate is about 15% for adults 18 to 79 years of age. Actual prevalence ratios may vary widely in specific sub-groups of the population and in accordance with differing methods and criteria of ascertainment. For example, the actual numbers of hypertensives in the general population of the US, detectable by two-stage screening, may be closer to 8 or 9 million. On the other hand, the current failure generally of detection of hypertension would suggest that the entire adult population must be screened periodically - and this number is greater than 126 million. The implications of these considerations for undertaking screening and management programmes are discussed briefly.

New instruments for measuring blood pressure.

The development of the conventional indirect method of blood pressure measurement was essentially complete by 1905, 70 years ago. The method has certain shortcomings, but these can be offset to a large degree by control over conditions of measurement, provision of proper apparatus, and intensive training of observers. Still, there are potential advantages which might be met by an acceptable automated device. An experimental evaluation of five such devices led to rejection of each of them on grounds of inadequate measurement performance, mechanical failures, or both. Only the Random-Zero device (Hawksley) among the instruments tested, gave good performance in comparison with the conventional method and was free of serious mechanical disadvantages. Evaluation of new devices will continue to be of great importance, and proposed guidelines for such studies are reviewed.

Blood pressure and obesity in childhood and adolescence. Epidemiologic aspects.

Blood pressure and body mass index (BMI) are first considered independently, and then jointly, on the basis of both cross-sectional and longitudinal epidemiologic studies. The relations between these two attributes are investigated further by analysis of the "velocity curves" of age increments, from ages 6 to 24, in both blood pressure (systolic and fifth-phase diastolic) and BMI, from data from the US Health and Nutrition Examination Survey, 1971-1974. The results of both reported studies and the present exploratory analysis indicate sometimes strong but quite variable relations between blood pressure and BMI, which differ by age, gender, and the particular blood pressure measure under consideration.

Birth cohort evidence of population influences on blood pressure in the United States, 1887-1994.

PURPOSE: Mean blood pressure (BP) has declined in the U.S. for several decades. It is unknown to what extent this decline was due to treatment of persons with recognized high BP or to population-wide influences on BP. Treatment would shift only the highest values lower, whereas, population-wide influences on BP would shift the entire distribution downward. METHODS: We examined changes in the distributions of systolic and diastolic BP (SBP, DBP) across birth cohorts born between 1887 and 1975 in 52,646 individuals examined in the National Health (and Nutrition) Examination Surveys between 1960 and 1994. The BP distributions were estimated as functions of age and birth-year to examine changes between birth cohorts. We postulated that the age-adjusted 10th, 50th and 90th percentiles of SBP and DBP had decreased in more recent versus earlier birth cohorts. RESULTS: The series of birth cohorts exhibited successively lower SBP and DBP at low, middle and high percentiles. In general, the 10th percentile of SBP decreased approximately 1.19 mmHg per decade of birth-year, whereas the 50th percentile decreased 2.40 mmHg per decade, and the 90th percentile decreased 4.62 mmHg per decade. A similar pattern of results was seen for DBP. CONCLUSIONS: The entire distribution of both SBP and DBP shifted downward. The downward shifts at the 50th percentile and below unequivocally demonstrate a strong prevention effect in the U.S. population during the period 1887 through 1975. This epidemiologic analysis indicates that population-wide influences can alter favorably the distribution of BP throughout the whole population.

Hospitalization rates for myocardial infarction among Mexican-Americans and non-Hispanic whites. The Corpus Christi Heart Project.

The rate of hospitalization for myocardial infarction was examined in the Corpus Christi Heart Project (CCHP), a prospective population-based surveillance program in a biethnic community of Mexican-Americans and non-Hispanic whites. During 12 months of ascertainment, a total of 740 patients hospitalized with definite (217) or possible (523) myocardial infarction were identified. Of the 740 subjects, 334 were Mexican-Americans (150 females and 184 males), 348 were non-Hispanic whites (138 females and 210 males), and 58 were of other ethnic backgrounds. The 1-year age-adjusted rates of hospitalization per 100,000 population were 427.4 and 276.9 among Mexican-American and non-Hispanic white females, respectively, and 721.4 and 502.6 among Mexican-American and non-Hispanic white males, respectively. The age-adjusted hospitalization rate ratios for Mexican-Americans in relation to non-Hispanic whites were 1.55 (95% confidence interval [CI]: 1.23 to 1.95) and 1.40 (95% CI: 1.15 to 1.70) for females and males, respectively. These results suggest that Mexican-Americans may have a greater burden of coronary disease than non-Hispanic whites.