Thiamin status of incarcerated and nonincarcerated adolescent males: dietary intake and thiamin pyrophosphate response

We measured thiamin status in 137 incarcerated and 42 nonincarcerated adolescent males by use of both dietary intake data and a standard biochemical assay, thiamin pyrophosphate (TPP) response. Average thiamin intake of the total group was greater than 120% of the age-specific recommended dietary allowance (RDA). Ninety-two percent of incarcerated subjects and 93% of nonincarcerated subjects were consuming greater than or equal to 70% of RDA. Although average daily thiamin intake of nonincarcerated subjects was significantly higher than that of incarcerated subjects, both groups appeared to be at minimal risk for marginal thiamin status. Comparison of TPP response values indicated that there was no significant difference between groups. However, approximately 24% of the total population appeared to have less than adequate RBC thiamin on the basis of current standards for TPP response. Neither dietary intake nor reported previous alcohol intake was correlated with TPP response. These discrepant findings raise questions about the usefulness of the TPP response as the sole indicator of marginal thiamin status.     

The transient hypercholesterolemia of major weight loss

Serum lipoproteins, body composition, and adipose cholesterol contents of six obese women were studied during and after major weight loss by very-low-calorie diets (VLCDs). Subjects started at 168 +/- 11% of ideal body weight, lost 30.3 +/- 3.7 kg in 5-7 mo, followed by 2+ mo in weight maintenance. Serum cholesterol fell from a prediet (baseline) value of 5.49 +/- 0.32 to 3.62 +/- 0.31 mmol/L (P less than 0.01) after 1-2 mo of VLCDs (nadir), after which it rose to 5.95 +/- 0.36 mmol/L (peak, P less than 0.01 compared with nadir and baseline) as weight loss continued. With weight maintenance, serum cholesterol fell to 4.92 +/- 0.34 mmol/L (P less than 0.05 compared with peak). Adipose cholesterol content did not change in peripheral (arm and leg) biopsy sites but rose significantly in abdominal adipose tissue with weight loss. We conclude that major weight loss was associated with a late rise in serum cholesterol, possibly from mobilization of adipose cholesterol stores, which resolved when weight loss ceased.     

Nutrition labels in bar graph format deemed most useful for consumer purchase decisions using adaptive conjoint analysis

This study estimated the effects of changing multiple levels and combinations of nutrition information format, load, expression, and order on consumers' perceptions of label usefulness in purchase decisions using adaptive conjoint analysis. A shopping mall intercept survey, which was administered by a marketing research firm, assessed consumer preferences for 12 label alternatives produced on Campbell's soup cans to portray nutrition information realistically; 252 of 258 respondents completed the computer interactive interview. Consumers significantly preferred the bar graph format to the bar graph/nutrient density and traditional label formats. Consumers considered the bar graph/nutrient density format to be as useful as the traditional label format. There was a highly significant difference among the three levels of information load; the most information load was preferred regardless of nutrient importance. Consumers significantly preferred nutrition information stated in absolute numbers and percentages vs in absolute numbers only in traditional, or in percentages only expressions. There was a significant difference between consumer preferences for the two types of information order. The findings indicate that consumers clearly preferred the nutrition label that displayed all nutrient values using a bar graph format, offered the most information load, and expressed nutrient values using both absolute numbers and percentages. Consumers also preferred nutrition information rearranged in an order that grouped nutrients that should be consumed in adequate amounts on the top, calories in the middle, and nutrients that should be consumed in lesser amounts on the bottom of the label.     

Family-oriented nutrition intervention for a lipid clinic population

We have developed a unique, family-oriented approach to lowering plasma cholesterol concentrations in persons with familial hyperlipidemias. The approach includes individual clinic visits and group nutrition classes and uses dietary goals outlined in The New American Diet. A series of 13 nutrition classes is presented to small groups, usually composed of relatives from pedigrees with familial hypercholesterolemia or other familial hyperlipidemias. Dietary action goals, cooking demonstrations, food tasting, and finger-stick plasma cholesterol determinations are important components of the classes. Problem-solving discussion is encouraged in the group. Over the past 4 years, 143 hyperlipidemic individuals, along with at least 94 unaffected family members, have participated in 31 groups, which have met for at least six classes. Many clinic participants lower plasma cholesterol by 20% or more. Keys to the success of this program include emphasizing dietary therapy, using the family setting for nutrition intervention, providing hands-on experience with food and recipes, promoting problem solving for dietary action goals, measuring blood cholesterol during classes, and encouraging long-term follow-up for participants with physicians and dietitians.     

A feasibility study of quantitative respirator fit testing by controlled negative pressure

The feasibility of using a direct measure of respirator leakage flow rate as a quantitative index of respirator face seal fit has been explored through the use of a new controlled negative pressure method. The method is based on exhausting air from a temporarily sealed respirator facepiece at a rate sufficient to generate and then sustain a constant negative pressure inside the facepiece while the wearer holds his breath. The magnitude of the negative pressure is preselected to replicate the mean inspiratory pressure inside the mask during normal wear. With the air-purifying paths into the respirator temporarily blocked, measurement of the exhaust flow rate yields a synonymous measure of the leakage flow rate into the mask during inspiration under normal use conditions. The feasibility of using the new method to quantify respirator fit was assessed in a preliminary study that compared its performance with a quantitative fit test method based on the use of dichlorodifluoromethane as a challenge agent. Study data exhibit a high degree of correlation (r greater than 0.99) and no significant difference between the two methods over a range of controlled mask leakage rates. A major advantage of the new method is that a worker can be fit tested with his assigned respirator because the method does not require a destructive sampling probe. Other significant benefits compared to current methods used to quantify respirator fit appear to include (1) ease of test administration, (2) simplicity of test components, (3) lack of a potentially toxic challenge agent, (4) a straightforward calibration procedure, (5) multiple test capability, (6) immediacy of test results, and (7) field portability of the test system.     

Adipose tissue fatty acid composition and its relations to diet and plasma lipid concentrations in hemodialysis patients

Adipose tissue fatty acid composition, serum lipid profile, and dietary intake of 37 patients on maintenance hemodialysis were studied. In August 1982, 1984, and 1986, analyses were carried out in 15 normotriglyceridemic (NTG) and 22 hypertriglyceridemic (HTG; type IV hyperlipidemia) patients. No correlations were found between dietary intake of polyunsaturated fatty acids (PUFAs), ratio of polyunsaturated to saturated fatty acids (P-S ratio), and carbohydrate content on the one hand and serum lipid concentrations on the other in the two groups. Adipose tissue linolenic acid correlated negatively with serum cholesterol in both groups. Strong correlations were found between dietary intake of PUFAs and adipose tissue linoleic acid content, between PUFAs and the double-bond index, between P-S ratio and adipose tissue linoleic acid content, and between P-S ratio and the double-bond index. No significant differences in dietary intake or adipose tissue fatty acid composition were observed between NTG and HTG patients. Thus, no evidence was found for exogenous dietary influences on serum lipid concentrations. The adipose tissue linoleic acid content did reflect the dietary intake of PUFAs.     

Relative importance of carbohydrate and protein sources in the differential effects of soy-based vs casein-based formulas on bone minerals in rats

Studies reported here examine the extent to which differences in the source of protein (soy vs casein) and of carbohydrate (absence or presence of lactose) may be responsible for differential effects of soy-based and casein-based infant formulas on bone minerals. Growth and bone minerals were measured in rats fed casein-based or soy-based diets with or without lactose. Analysis of variance indicated that presence of lactose in the diets increased calcium, phosphorus, magnesium, and zinc concentrations in the vertebrae (P less than 0.02) and also increased magnesium (P less than 0.01) and zinc (P less than 0.05) in femur and tibia-fibula. In contrast, the source of protein had an effect only on bone magnesium concentration, with the soy protein resulting in lower magnesium retention in all bones studied (P less than 0.05). These data suggest that differences in lactose content rather than in the source of protein may be mainly responsible for the differential effects of milk-based and soy-based infant formulas on bone minerals.     

Human immunodeficiency virus infection in urban Rwanda. Demographic and behavioral correlates in a representative sample of childbearing women

OBJECTIVE.--To determine behavioral and demographic risk factors for human immunodeficiency virus (HIV) infection in central Africa. DESIGN.--Cross-sectional survey. SETTING.--Kigali, Rwanda. PARTICIPANTS.--A representative sample of 1458 childbearing women aged 19 to 37 years who were recruited from outpatient prenatal and pediatric clinics at the only community hospital in the city. MAIN OUTCOME MEASURE.--Antibodies to HIV assessed by enzyme immunoassay and confirmed by Western blot or indirect immunofluorescence. RESULTS.--The HIV seroprevalence was 32% overall. Infection rates were higher in women who were single, in those in steady relationships that began after 1981, and in the 33% of women reporting more than one lifetime sexual partner. Women in legal marriages or monogamous partnerships had lower rates of infection, but even low-risk women had prevalences on the order of 20%. History of venereal disease in the past 5 years, although the strongest risk factor in a multiple logistic analysis (odds ratio, 2.7; 95% confidence interval, 2.0 to 3.7), was reported by only 30% of those infected. Having a male sexual partner who drank alcohol or who had higher income were significant risk factors for HIV infection in the multivariate analysis, but use of oral contraceptives and having an uncircumcised partner were not. CONCLUSIONS.--The epidemic of the acquired immunodeficiency syndrome in Rwanda has spread beyond high-risk groups to the general population of women without known risk factors. For most of these women, a steady male partner is the source of their HIV risk and therefore a vital target for intervention efforts.     

Clinical decision making: from theory to practice. The individual vs society. Resolving the conflict

Eddy argues for reform of the American health care system. In seeking health coverage, he explains, there are two positions: the first, that of society, seeks to allocate services efficiently; the second, that of the patient, seeks to optimize individual patients' care. Using his illustration of breast cancer coverage from a previous JAMA article (1991 Mar 20; 265 (11): 1446+), Eddy contends that a tradition of decision-making from the second position is the root of present health care inefficiencies. Eddy's ideal would be complete information to physicians and patients about service costs, benefits, and financial feasibility, and an agreed-upon standard of fair resource allocation, based on the threshold of a specific measure of benefit per resource. To approach this ideal, he concludes, we must recognize the problem, pursue education about service costs and benefits and people's desires of the system, and identify and review services that presently are inefficiently utilized.