Lipid levels in adults with cystic fibrosis.

OBJECTIVE: To examine the hypothesis that an energy-dense, high-fat diet, which is necessary to maintain weight in adults with cystic fibrosis, does not result in high serum cholesterol levels. DESIGN: Dietary, anthropometric, and biochemical data were correlated. SETTING: A cystic fibrosis center in Pittsburgh, Pa. SUBJECTS: Thirty-one adults with cystic fibrosis, 50 obligate carriers of the cystic fibrosis gene, and 26 controls who did not have cystic fibrosis. MAIN OUTCOME MEASURES: Adults with cystic fibrosis had a lower mean serum cholesterol level and higher mean intakes of energy and fat than controls. STATISTICAL ANALYSES PERFORMED: Student's t test was used to determine the statistical significance between two means. Univariate correlation coefficients were determined to measure the relative intensity of association between two variables. RESULTS: Mean total serum cholesterol levels in men with cystic fibrosis was 3.1 mmol/L vs 4.7 mmol/L in male controls (P < .001). Mean total serum cholesterol levels in women with cystic fibrosis was 3.2 mmol/L vs 4.3 mmol/L in female controls (P < .001). Three adults with cystic fibrosis and no signs of pancreatic insufficiency had serum cholesterol levels in the high normal range. Carriers had serum lipid levels in the same range as the controls. CONCLUSIONS/APPLICATIONS: The findings indicate that a high-energy, high-fat diet does not raise serum lipid levels in those patients with cystic fibrosis and pancreatic insufficiency. However, those individuals with cystic fibrosis and normal pancreatic function may be at the same risk as the general population for developing high serum lipid levels. They should have their serum lipid levels monitored and be given appropriate dietary recommendations.

Early infant diet and risk of IDDM in blacks and whites. A matched case-control study.

OBJECTIVE: To investigate the role of early infant feeding in the development of insulin-dependent diabetes mellitus (IDDM) and to determine whether an association exists in both blacks and whites. RESEARCH DESIGN AND METHODS: Black and white diabetic subjects were recruited from the Allegheny County and Children's Hospital of Pittsburgh IDDM Registries. Extensive infant diet histories were obtained from the diabetic subjects and their nondiabetic siblings, who were used as nondiabetic control subjects. Each diabetic subject was matched outside his/her family to an unrelated nondiabetic control subject on birth order, birth year (+/- 2 yr), and race, which resulted in 211 case-control pairs with a mean birth year of 1967. RESULTS: In whites, diabetic subjects were less likely to have been breast-fed than control subjects (odds ratio [OR] 0.5, 95% confidence interval [CI] 0.3, 0.9). Breast-feeding prevalence did not differ between black diabetic subjects and control subjects. Duration of overall and exclusive breast-feeding did not differ between diabetic and control subjects in the black and white cohorts. The following analyses, which examined whether the timing of the first breast milk substitute to which the infant was exposed differed between diabetic and control subjects, were conducted for exposure to any breast milk substitute and to breast milk substitutes that were cow's milk based. In whites, age at exposure to any breast milk substitutes and cow's milk-based substitutes were similar between diabetic and control subjects. In blacks, the first exposure to breast milk substitutes occurred significantly earlier for any substitute (5.1 vs. 11.9 wk, P = 0.02) and marginally earlier for cow's milk-based substitutes (3.9 vs. 8.5 wk, P = 0.07) in diabetic subjects compared with control subjects. The first exposure to breast milk substitutes was more likely to occur by 3 mo of age in black diabetic subjects compared with black control subjects (OR 3.3, 95% CI 1.1-10.0) after adjusting for maternal age at birth. The addition of breast-feeding status to the model only slightly weakened this association in blacks. CONCLUSIONS: The analyses of this study cohort suggest that the observed protective effect of breast-feeding on the risk of IDDM may be related to differences in the age at exposure to breast milk substitutes in blacks but not in whites.

Cholesterol screening in childhood: sixteen-year Beaver County Lipid Study experience.

To determine the extent to which cholesterol measured in childhood is predictive of values in adulthood, the investigators conducting the second follow-up of the Beaver County Lipid Study tracked the cholesterol values of 295 adults who had initially participated as children (ages 11 to 14 years) in a countywide school screening program. The follow-up study was conducted 16 years after the initial study, when the participants had reached a mean age of 28 years. The overall correlation (r) between baseline (1972-1973) total cholesterol values and the values found at the present follow-up was 0.44 (p less than 0.0001). Women had a higher correlation (r = 0.51) than men (r = 0.38). In addition, the efficacy of childhood screening for cholesterol levels was assessed by considering currently recommended borderline values (greater than 175 mg/dl (4.6 mmol/L) for children and greater than 200 mg/dl (5.2 mmol/L) for adults) as a "positive" test result. The sensitivity of screening at age 12 years for predicting elevated adult total cholesterol concentrations was 63%, specificity was 67%, and the predictive value of a positive test result was 47%. Comparison of false-positive results (above the borderline cutoff point as a child but not as an adult) and false-negative results (below the borderline cutoff point as a child but above it as an adult) showed that male subjects with false-positive results smoked significantly less than those with false-negative results (p less than 0.05) and had a greater improvement during the preceding 7 years in cholesterol-lowering dietary practices (p less than 0.01). Female subjects with false-positive results smoked significantly less than those with false-negative results (p less than 0.05), were less overweight (p less than 0.05), and had a lower prevalence of oral contraceptive use (p less than 0.01). These results support the potential value of screening for hypercholesterolemia in childhood on a population basis. Although some subjects were misclassified as a result of childhood screening, some of this misclassification was associated with adopting changes that a screening and intervention program would be designed to promote--nonsmoking, weight control, and a prudent diet.

Zinc status of children with sickle cell disease: relationship to poor growth.

We examined the zinc status of 80 children with sickle cell disease (SCD) and 44 disease-free sibling controls aged 3 to 18 years. For both patients and controls, variations in serum zinc by age, type of hemoglobinopathy, and growth status were measured. The mean serum zinc concentration of patients was significantly lower than for controls (77.8 +/- 9.9 vs. 82.2 +/- 9.8 micrograms/dl, mean +/- 1SD, P less than .05). Serum levels of alkaline phosphatase (AP) and retinol-binding protein (RBP), two zinc-dependent proteins, were also lower among patients (AP: 171 +/- 66 vs. 243 +/- 97 IU/L, P less than .001; RBP: 1.92 +/- .9 vs. 2.77 +/- .9 mg/dl, P less than .001). Patients greater than or equal to 12 years of age (n = 34) had significantly lower zinc levels than those less than 12 years (74.5 +/- 8.4 vs. 80.3 +/- 10.3 micrograms/dl, P less than .01), and children with homozygous SCD (Hb SS, n = 55) had a more pronounced deficiency than those with a variant hemoglobinopathy (76.3 +/- 8.9 vs. 81.5 +/- 11.5, micrograms/dl, P less than .05). Patients classified as having "poor" growth (height-for-age less than 5th percentile, n = 24) had a lower serum zinc level than those with "normal" growth (72.8 +/- 8.0 vs. 79.8 +/- 10.0 micrograms/dl, P less than .01). Dietary intake data, body mass index, and serum total protein and albumin levels were similar for patients and controls, suggesting that zinc deficiency in SCD does not relate to inadequate dietary intake. The origin of low serum zinc levels in children with SCD is more likely to relate to factors such as increased urinary zinc excretion, chronic intravascular hemolysis, and/or zinc malabsorption.

Serum lysosomal hydrolases in cystic fibrosis.

The activities of a number of lysosomal hydrolases were determined in sera from 100 patients with cystic fibrosis (CF), age 2-35 yr, and age-matched controls: beta-hexosaminidase activity was significantly elevated (p less than 0.005) in CF patients from all age groups. alpha-Mannosidase activity was increased only in the older CF patients (greater than 13 yr). The following enzyme activities were not altered in CF serum: alpha-fucosidase, beta-glucuronidase and acid phosphatase. The abnormal patterns of serum alpha-mannosidase and beta-hexosaminidase in CF cannot be explained by pancreatic disease or undernutrition, since serum values of these hydrolases in patients with anorexia nervosa or acute pancreatitis were not altered. However, the altered activities of the alpha-mannosidase and beta-hexosaminidase were proportional to the degree of pulmonary insufficiency in the CF group, indicating that these changes are probably a secondary consequence of the primary disease process. Except for beta-hexosaminidase, because differences in the serum hydrolases in CF do not become apparent until the second decade of life, determinations of lysosomal enzyme activities in serum will probably be of little diagnostic value.

Dietary vitamin A deficiencies and stomach cancer.

The hypothesis of vitamin A intake deficiencies serving as an antecedent factor in the development of stomach cancer was assessed employing a case-control design. Interviews of proxy informants for 111 cases and a pair-matched control group were conducted using a food frequency questionnaire from which an averaged vitamin A intake index was calculated. Stomach cancer cases showed a significantly higher proportion with lowered total vitamin A intake levels (odds ratio = 1.71) which remained constant across sex and socioeconomic status groupings. These results demonstrated a consistency with previous related studies vis-à-vis the strength and specificity of the putative association, a moderate (but statistically nonsignificant) dose-response curve, proper temporal association, and biologic plausibility.

Evaluation of clinical skills for nutrition counseling.

This report describes the procedures for and feasibility of an evaluation program that provides a direct assessment of the use of specific clinical skills during an interview with a simulated patient. The specific aims of this evaluation were to assess untrained graduate students in nutrition on their application of a set of 31 specific clinical skills for resolving dietary adherence problems. Each student conducted two interviews with each of two different simulated patients with hyperlipidemia presenting typical problems following a diet low in saturated fat and cholestrol. The evaluation program provided analyses that identified the strengths and deficits of each student and the performance of the entire group. It is suggested that the evaluation program offers a practical, objective method for examining the entry-level clinical skills of students in training and may be useful in other educational programs (eg, in-service, continuing education workshops).

Growth patterns by age and sex in children with sickle cell disease.

We examined growth patterns by age and sex in 133 children and adolescents with sickle cell disease. These patients are estimated to be representative of the total population aged 1 to 18 years with sickle cell disease in a large metropolitan area. Median height and weight curves constructed from serial growth data available for all 133 children demonstrated impairment in height and weight at all ages and in both sexes. Analysis of growth trends by age reveals a pattern of increasing deficit with increasing age; boys are more severely affected than girls. Growth velocity curves constructed for a series of 13 adolescents with sickle cell disease illustrate the marked delay in the onset of the normal pubertal growth spurt in these patients.