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Biomedical subjects

C L Shear

Publications and source records attributed to C L Shear.

At least 37 records · Page 2Linked to original sources
PubMed1987

Designation of children with high blood pressure--considerations on percentile cut points and subsequent high blood pressure: the Bogalusa Heart Study.

The effects of changing the percentile cut points of prior blood pressure measurements (both single and serial examinations) on prediction of subsequent high blood pressure, and of the definition of subsequent high blood pressure were assessed in 1,501 children from Bogalusa, Louisiana. Subjects were 2-14 years old at initial examination (year 1, 1973-1974) and were reexamined three, five, and eight years after the initial examination. Increasing the stringency of the prior measurement cut point resulted in increased specificity and positive predictive value, but decreased sensitivity and negative predictive value. For prediction of subsequent systolic blood pressure at the 90th percentile from year 1 levels, increasing the year 1 cut point from the 80th to the 95th percentile resulted in decreased sensitivity from 42.8 to 13.0%, and increased specificity from 83.0 to 97.3%. For systolic pressure, requiring all prior serial measurements to be above specified cut points resulted in further increases in specificity (maximizing at 100%) and decreases in sensitivity (minimizing at 2.1%). Using a year 1 cut point at the 90th percentile, increases in the definition of subsequent high blood pressure (from the 80th percentile to 140/90 mmHg or on treatment, respectively) resulted in increased sensitivity (from 20.5 to 33.3%) and negative predictive value, with decreasing specificity (from 93.9 to 91.3%) and positive predictive value. The results indicate that use of stringent criteria (serially at the 95th percentile) to identify children at risk for future essential hypertension will result in a substantial portion of the childhood population who will escape early identification but who will develop adult hypertension. Less stringent criteria will increase sensitivity and thereby provide the opportunity for primary prevention to a larger portion of the general childhood population who are at high risk for adult hypertension.

Adolescent↗
PubMed1987

Body fat patterning and blood pressure in children and young adults. The Bogalusa Heart Study.

The relationship of central body fat (measured by subscapular skinfold) and peripheral body fat (measured by triceps skinfold) to blood pressure was investigated in 3784 subjects aged 5 to 24 years old from the biracial community of Bogalusa, Louisiana. After adjustment for height, age, sex, and race, significant relationships were found for both central body fat (r = 0.19 and 0.14, p less than 0.0001) and peripheral body fat (r = 0.15 and 0.12; p less than 0.0001) with systolic and diastolic (fourth phase) blood pressure, respectively. However, the relationship between peripheral body fat and blood pressure, after controlling for the level of central body fat, was negligible (r = 0.00 and 0.01 for systolic and diastolic blood pressure, respectively). In contrast, the central body fat-blood pressure relationship remained statistically significant even after controlling for the peripheral body fat level. For central body fat, the partial correlations with systolic blood pressure were highest in young children (r = 0.15), dropped slightly during adolescence (r = 0.12), and became nonsignificant only in 18- to 24-year-old female subjects; correlations remained high in both black and white 18- to 24-year-old male subjects (r = 0.18 and 0.16, respectively). Mean levels of systolic blood pressure from the lowest to the highest quartile of central body fat ranged from 100.4 to 108.9 mm Hg. The adult hypertension-central body fat relationship, which has been shown by others, appears to exist in children. Continued efforts at early identification and prevention of obesity in children are warranted.

Adipose Tissue↗
PubMed1987

Persistence of juvenile-onset obesity over eight years: the Bogalusa Heart Study.

The persistence of obesity and overweight over eight years was assessed in a biracial (Black-White) cohort of 1,490 two-to 14-year-olds. Initial levels of triceps skinfold thickness (TRSF) and Rohrer index (weight/height3) were moderately predictive of subsequent levels: r = 0.54 and 0.67, respectively. However, TRSF and Rohrer index tended to track most strongly in Black females (r = 0.64 and 0.72) and less well in both White females (r = 0.45 and 0.57) and preschool children (r = 0.45 and 0.54). Based on elevated levels of TRSF or Rohrer index, children were classified as obese or overweight, respectively. Of the 222 children who were initially above the 85th percentile for TRSF, 43 per cent remained obese after eight years. Persistence of overweight was slightly greater at follow-up, with 50 per cent of initially overweight children staying above the 85th percentile for Rohrer index. Severe, initial obesity/overweight (greater than 95th percentile) and consecutively elevated levels increased the probability of remaining obese/overweight. Results indicate that moderate, juvenile-onset obesity is malleable, but that the child who is extremely obese over consecutive examinations is likely to become an obese adult.

Adolescent↗
PubMed1987

Cardiovascular risk factors from birth to 7 years of age: the Bogalusa Heart Study. Blood pressure.

BP was measured in 440 children followed longitudinally from birth to 7 years of age in Bogalusa, LA. Levels, trends, and determinants of BP were evaluated in this newborn cohort. Both systolic and diastolic BP levels remained relatively constant between the ages of 6 months and 7 years. BP levels varied between the different instruments, and differences were also noted between measures obtained using the same instrument before and after venipuncture. White children were noted to have slightly higher levels of systolic and diastolic BP pressure at 6 months and 1 year of age, even after adjustment for body size. Significant prediction of year 7 BP rank occurred as early as 6 months of age for systolic and at 1 year of age for diastolic BP levels. Body size was inconsistently related to BP levels from ages 6 months through 4 years, but the relationship was stronger and more consistent with changes in body size. Of interest is the relatively constant levels of indirect BP during this period of rapid growth, as measured by currently available instruments. These data emphasize the importance of cardiovascular risk factor measurement during early life and of the need to improve methods of indirect BP measurement in infancy.

Age Factors↗
PubMed1986

The relation of apolipoproteins A-I and B in children to parental myocardial infarction.

Clinical studies suggest that serum levels of apolipoproteins A-I and B may be more strongly related to coronary artery disease than are their respective lipoprotein-cholesterol fractions. Therefore, we assessed the association between levels of apolipoprotein B, apolipoprotein A-I, lipids, and lipoprotein cholesterols in children and the reported histories of myocardial infarction in their parents in a survey of 2416 black and white school-age children. As compared with children whose fathers did not report a myocardial infarction, those whose fathers reported having had an infarction (n = 139) had a lower mean level of apolipoprotein A-I (137 vs. 141 mg per deciliter; P = 0.04) and a lower ratio of low-density lipoprotein cholesterol to apolipoprotein B (1.08 vs. 1.11; P = 0.007), along with a higher ratio of apolipoprotein B to apolipoprotein A-I (0.64 vs. 0.61; P = 0.04). These associations existed independently of the children's race, sex, age, and history of obesity, smoking, alcohol intake, and use of oral contraceptives. Children whose mothers reported having had a myocardial infarction (n = 56) had no decrease in the ratio of low-density lipoprotein cholesterol to apolipoprotein B, but they tended to have an elevated ratio of apolipoprotein B to apolipoprotein A-I. In contrast, serum lipoprotein-cholesterol fractions in children were not related to myocardial infarctions in either parent. These results provide further evidence that apolipoproteins are more strongly related to the risk of cardiovascular disease than are lipoprotein-cholesterol fractions.

Adolescent↗
PubMed1986

Description of a large pedigree with an adverse lipoprotein cholesterol phenotype: the Bogalusa Heart Study.

A large pedigree (N = 356) with a high prevalence of heart disease and associated adverse lipoprotein phenotype was studied. The adverse lipoprotein phenotype is characterized by both low levels of high-density-lipoprotein cholesterol (HDL-C) alone (16.3%) and in combination with other adverse lipoprotein levels (12.8%). In all, 44.2% of all pedigree members had at least one adverse lipoprotein level. Analysis of mating types showed that all lipids and lipoproteins possess familial clustering with 25-36% of offspring above median levels when both parents had levels below the median, while 67-83% had levels above the median when both parents had levels above the median. Using adjusted lipid and lipoprotein levels, a statistically significant linear trend was found between the degree of relationship to pedigree members with heart disease, and both the low-density-lipoprotein cholesterol/high-density-lipoprotein cholesterol (LDL-C/HDL-C) ratio (P less than .05), and the very-low-density-lipoprotein cholesterol (VLDL-C; P less than .01) level. A similar analysis using the prevalence of adverse lipoprotein levels as the dependent variable and degree of relationship to heart diseased pedigree numbers as the independent variable showed significant (P less than .05) relationships with VLDL-C and the LDL-C/HDL-C ratio. Further genetic analyses of this pedigree may reveal genetic mechanisms responsible for the familiality of lipoprotein levels in this pedigree.

Adolescent↗
PubMed1986

Medical care at the 1982 US Festival.

The 1982 US Festival, a three-day outdoor rock music festival, attracted close to 410,000 people. Through a private contractor, a group of physicians participated in the design, administration, and implementation of medical care for this event. Basic ambulatory care was provided by a multitiered approach, using emergency medical technicians, registered nurses, medical health counselors, and physicians. A total of 2,623 encounters required examination and evaluation by health professionals. Thirty-eight percent (1,014 cases) involved minor surgical trauma. Extreme environmental conditions, including temperatures exceeding 114 F, high winds, and unusually high dust concentrations, were thought to be responsible for 361 (13.6%) cases of reactive airway disease and 184 (7%) cases of heat exhaustion. There were 91 transports, of which 12 were classified as major casualties; there were no deaths.

Ambulances↗
PubMed1986

Cigarette smoking initiation and longitudinal changes in serum lipids and lipoproteins in early adulthood: the Bogalusa Heart Study.

To examine the influence of cigarette smoking initiation on serum lipid and lipoprotein changes in early life, 747 nonsmoking 9- to 17-year-olds from the biracial community of Bogalusa, Louisiana were reexamined five to six years following an initial screening. Upon reexamination in 1981-1983, 147 reported smoking cigarettes (mean duration, 3.5 years; median number of weekly cigarettes, 20). Compared with nonsmokers, persons who began smoking had more unfavorable changes in serum triglycerides and lipoprotein cholesterol levels during follow-up, independently of age, sexual maturation, obesity, alcohol consumption, and oral contraceptive use in females. Smoking initiation was not associated with increases in serum total cholesterol levels, but compared with nonsmokers, white males and white females smoking three or more packs weekly showed additional mean increases of 13.2 and 11.6 mg/dl in low density lipoprotein cholesterol, additional 5.9 and 2.4 mg/dl increases in very low density lipoprotein cholesterol (VLDL-C), and additional decreases of 15.6 and 9.2 mg/dl in high density lipoprotein cholesterol levels, respectively. Black smokers showed larger increases in serum triglycerides and VLDL-C levels than did black nonsmokers. These findings indicate that the start of even modest cigarette smoking may have potentially long-term atherogenic effects. Prevention of smoking in early life should therefore be an important aspect of cardiovascular disease intervention.

Adolescent↗
PubMed1986

Satisfaction of continuity patients in a family medicine residency--validation of a measurement tool.

Patient satisfaction with resident physicians and patient satisfaction with faculty physicians was investigated in three clinical centers of a county hospital-based family medicine residency. Only patients in a continuity relationship (minimum 5 visits) were studied. Utilizing a previously validated Patient Satisfaction Questionnaire (PSQ), the dimensions of access, availability, continuity, finances, physician humaneness, and physician quality/competence were measured. Although there was little discriminant power between the measures of physician humaneness and quality/competence of care, overall internal validity was high. Availability and finances created the most dissatisfaction. Residents' care was reported to be as satisfying as that delivered by faculty physicians. Differentiation between system dependent factors and physician-dependent factors may be difficult among patients with a demonstrated continuity relationship. Nevertheless this study demonstrated a high internal validity for the short form of the PSQ in yet another practice setting. This instrument is available for further investigation in clinical settings.

Adult↗
PubMed1986

Cardiovascular risk factors and their modification in children.

Normal levels and trends of cardiovascular disease risk factors in childhood have been well documented by numerous epidemiologic surveys. Expected levels of blood pressure, lipids and lipoproteins, and body size can be determined by the child's physician using race- and gender-specific grids. These grids allow for the identification and follow-up of children with high-risk profiles. Evidence of increased left ventricular mass and vascular changes in renal arteries in association with childhood blood pressure level along with atherosclerotic fatty streak and fibrous plaque development in the aorta and coronary arteries shows that children with elevated risk factors are at risk for early target organ damage. These data demonstrate the potential importance of early intervention on the natural history of cardiovascular disease. Based on our own data from the Bogalusa population, as well as evidence from other epidemiologic investigations in children, the following recommendations can be made, regardless of the risk factor variable under consideration: Cardiovascular disease risk factor variables should be measured carefully and in a serial manner to classify a child as abnormal. Serial measurements serve to reduce the effect of regression to the mean and increase the predictive value of the measurements. The misclassification of normal children into the high-risk category can be avoided by serial and replicate observations. Interventions that have attendant side effects (for example, pharmacologic therapy for high blood pressure) have to be measured against the effectiveness of diet, exercise, and other aspects of primary prevention. Risk factor levels consistently greater than the ninetieth percentile deserve medical attention. Care should be taken prior to using specific grids of normal levels of cardiovascular disease risk factors in children. The measurement techniques employed on individuals should be similar to those used by the epidemiologic study to generate the grids in a reference population. The grids should become part of the child's permanent medical record, as they provide a rapid visual assessment of the cardiovascular disease risk profile over time. High-risk trackers may require more intensive follow-up and will allow for early intervention and an assessment of the efficacy of the intervention program. In conclusion, cardiovascular disease risk factor screening in childhood is quick, effective, and inexpensive. The potential payoff in prevention of adult cardiovascular disease is enormous and allows the physician to provide more comprehensive care to a pediatric population.

Adolescent↗
PubMed1986

Value of childhood blood pressure measurements and family history in predicting future blood pressure status: results from 8 years of follow-up in the Bogalusa Heart Study.

The value of BP measurements and family history of cardiovascular disease in predicting future BP status was studied in 1,501 children, initially 2 to 14 years of age, who were examined four times during an 8-year period in the Bogalusa Heart Study. Correlation coefficients between year 1 and year 9 BPs were as follows for systolic and diastolic BPs, respectively: 0.41 and 0.35 (P less than .0001). These correlations were significant in all age groups. For children in the upper quartile of BP at any one prior examination, the percentage remaining in the year 9 upper quartile ranged from 41% to 52% for systolic BP and 35% to 44% for diastolic BP. Three serial BP measurements in the upper quartile increased the percentages remaining in the upper quartile to 68% for systolic BP and 62% for diastolic BP. Conversely, of those children not in the upper quartile of systolic BP at year 9, 96.8% did not have all three prior measurements in the upper quartile. Family history of hypertension was shown to independently predict year 9 systolic BP status. These results confirm the importance of serial BP measurements and family history of hypertension for the practicing physician.

Adolescent↗
PubMed1985

Tracking of serum lipids and lipoproteins in children over an 8-year period: the Bogalusa Heart Study.

Although children initially identified as having elevated levels of coronary heart disease risk factors tend to have elevated follow-up levels (track), a substantial proportion show regression to the mean. Relationships of both genetic and environmental factors to tracking of serum lipids and lipoproteins over an 8-year period were examined in children from a biracial community. Associations between initial and follow-up levels were similar at 3, 5, and 8 years of follow-up; however, differences between the race-sex groups were observed. Two initial measurements reduced the number of nontrackers (children with high initial and decreased follow-up levels). Fathers of children showing persistently elevated levels of either serum total cholesterol or triglycerides were more likely to have diabetes mellitus or to have had heart attacks than were fathers of nontrackers. Children tracking for elevated low-density lipoprotein cholesterol levels had larger increases in triceps skinfold thickness than did the nontrackers. Children consuming alcohol tended to have elevated levels of high-density and decreased levels of low-density lipoprotein cholesterol at follow-up. These observations indicate that the use of repeated serum lipid and lipoprotein determinations, along with measurements of obesity and information concerning family history of heart attack and diabetes mellitus, can aid in the prediction of future elevated serum lipid and lipoprotein levels.

Adolescent↗
PubMed1985

The relationship between parental history of vascular disease and cardiovascular disease risk factors in children: the Bogalusa Heart Study.

The relationship between parental history of vascular disease (heart attack, stroke, diabetes mellitus, and hypertension) and risk factor variables for cardiovascular disease was assessed in 3,312 offspring aged 5-17 years during the 1981-1982 school year in the biracial community of Bogalusa, Louisiana. Risk factors studied included systolic blood pressure, diastolic blood pressure, serum total cholesterol, triglycerides, and individual lipoprotein cholesterol (beta-, low density lipoprotein (LDL) cholesterol; pre-beta, very low density lipoprotein (VLDL) cholesterol; and alpha-, high density lipoprotein (HDL) cholesterol). Risk factors were adjusted for age, race, sex, and height (blood pressure only) prior to testing parental history effects. Univariate comparisons between risk factors in children and vascular disease in parents resulted in statistically significant increases in systolic and diastolic pressures associated with the presence of maternal or paternal hypertension (p less than 0.001). Paternal heart attack was also associated with elevations in diastolic pressure (p less than 0.01) of children. Maternal diabetes mellitus was associated with an increase in serum total cholesterol (p less than 0.05). Paternal diabetes mellitus and maternal heart attack (for female progeny only) were associated with increases in mean triglyceride levels of children. VLDL cholesterol results were similar to those for triglycerides. For HDL cholesterol, paternal diabetes mellitus was associated with a small decrease in mean levels (p less than 0.05). Dramatic increases to the highest decile of risk were found in association with the following parental disease combinations: paternal heart attack-paternal diabetes for serum total cholesterol (p less than 0.0001), maternal heart attack-paternal diabetes (p less than 0.001) and paternal stroke-maternal diabetes (p less than 0.0001) for LDL cholesterol. Multivariate analysis detected no significant effects of single parental vascular disease. However, paternal heart attack in combination with either diabetes mellitus or hypertension was statistically significant in their relationship to the risk factors overall.

Adolescent↗
PubMed1985

Diagnosis cluster frequency in a community-based family practice residency program. Comparison with large ambulatory data sets.

Ambulatory encounters in a community-based family practice residency program were analyzed using diagnosis clusters. During an 18-month period (July 1982 through December 1983), demographic information and clinical diagnoses for 44,453 successive patient visits were collected and stored in a computerized data base. The 30 most frequent diagnosis clusters accounted for 70% of all recorded clinical diagnoses. Comparison with NAMCS, USC-MAMP (Western Region) and Virginia studies revealed a younger, more indigent population with a higher frequency of visits for hypertension, prenatal and postnatal care, diabetes, chronic respiratory illness and congestive heart failure. Consistent with the other large ambulatory data sets, the general medical examination, hypertension and acute upper respiratory conditions were the most frequent diagnosis clusters. Differences with other reported data sets reflected the site-specific demographic characteristics of patients and providers, regional and environmental influences on the incidence of specific disease states and the relative abundance of other subspecialist physicians. Such local or regional data bases not only provide valuable information as to clinical content but also may help in identifying previously unrecognized health problems.

Adolescent↗
PubMed1984

Resident and parental perceptions of adolescent problems and family communications in a low socioeconomic population.

This cross-sectional survey of a low socioeconomic patient group was designed to determine the prevalence and severity of parentally perceived behavioral problems in adolescents as well as to investigate the correlation between such problems and single parenting, family communications, and medical care delivered. The sample population consisted of 79 parents and 121 teenagers selected from a family practice center. The medical record and telephone interview were the sources of information. Results include a parental perception of a high prevalence of problems with school grades (48 percent), school attendance (38 percent), and household problems (chores and sibling rivalry). Of low prevalence but high severity were perceived problems related to suicidal ideation, running away, sexual activity, and gang membership. Single-parent homes had a threefold higher incidence of behavioral problems, a greater degree of communication, and a lower use of community resources than two-parent families. None of the approximately 400 perceived behavioral problems listed by parents was found in the family physicians' master problem list. The results indicate the need for physician education of low socioeconomic and single-parent patients with regard to communication and coping style. In addition, it appears that training programs should provide more education in the care of adolescents.

Adolescent↗
PubMed1984

Do-not-resuscitate orders in a county hospital.

The use of the do-not-resuscitate order has become accepted medical practice. To date, however, no study has been done of how often it is used or factors associated with its use. Reports of all deaths of inpatients occurring during calendar year 1981 at San Bernardino County Medical Center were eligible for study. Retrospective review of the 237 cases indicated that a do-not-resuscitate order had been written for 165 (69.6%) of the patients. Comparison of reports of those for whom such an order had been written with those for whom no order had been written indicated that a do-not-resuscitate order was not associated with age, sex, ethnicity or pay status. Indices of mental clarity, however, were associated with orders not to resuscitate; those patients residing in nursing homes, and not alert and oriented on admission were overrepresented in the group given this order. Primary discharge diagnosis was also associated with such an order, as was an increased duration of hospital stay.

California↗
PubMed1983

Provider continuity and quality of medical care. A retrospective analysis of prenatal and perinatal outcome.

It is often assumed that family physicians are able to provide a higher quality of medical care because of the greater degree of continuity inherent in their practices. The authors attempted to measure the association between continuity and quality of medical care using pregnancy as a tracer condition. Using a retrospective cohort study design, two groups of pregnant women were identified--those cared for in the family practice (FP) centers and those cared for in the obstetric (OB) clinics. Process and outcome of medical care were measured along with patient satisfaction. Provider continuity, as measured by the SECON value, was much higher in the FP group, and was highly correlated with the presence of an "attitudinal contract" between patient and physician. Although not statistically significant, four times as many newborns from the OB group were admitted to the neonatal intensive care unit. FP group newborn weight averaged 220 grams more than the OB group (P less than 0.05). This difference remained after control for covariates. While not reaching statistical significance, patient satisfaction scores tended to be higher for the FP group in two of three categories measured. The results suggest that continuity of care was associated with better patient outcome and satisfaction. Directions for causal interpretation and future research are discussed.

Adult↗