The potential for entomophagy to address undernutrition

The use of insects as food for humans has the potential to substantially reduce undernutrition worldwide. The Food and Agriculture Organization of the United Nations estimates that 805 million people are undernourished, with a total food energy deficit of 67.6 billion kcal/day (84 kcal/day/person). Calculations in this article suggest that this deficit could theoretically be reduced or eliminated through edible insect rearing, utilizing organic side streams as feed, on 15,586 to 92,976 ha.

Unmet eye care needs among U.S. 5th-grade students

BACKGROUND

There is substantial evidence of a disparity in access to eye care services among adults in the U.S.; however, little is known about health disparities for children's eye care.

PURPOSE

The goal of the study was to assess the prevalence of and risk factors for 5th-grade students' unmet eye care needs.

METHODS

Data were collected from 5147 5th-grade students (aged 10-11 years) and their parents and primary caregivers (hereafter "parents") participating in the Healthy Passages study between fall 2004 and summer 2006 (analyzed in 2011). Logistic regression estimated the probability of inability to afford needed eyeglasses and absence of vision insurance coverage.

RESULTS

1794 5th-grade students wore eyeglasses or were told that they need eyeglasses; 13.7% of their parents were unable to afford needed eyeglasses (new prescription or replacement) for their children; 27.4% of their parents reported no vision insurance coverage for eye examinations and eyeglasses. After controlling for confounders, parents without general children's health insurance were more likely to report being unable to afford eyeglasses than those with health insurance (Medicaid, SCHIP, private/other insurance; adjusted percentages: 22.5% vs 10.9%, 9.6%, 12.5%; all p<0.05). Parents with lower income were more likely to report being unable to afford children's eyeglasses even after controlling for all other factors (17.6% with income <$15,000 vs 2.7% with income ≥$70,000; p<0.001).

CONCLUSIONS

SES and health insurance status are strongly associated with 5th-grade students' unmet eye care needs. Policies targeting socioeconomically disadvantaged groups and those without insurance may be needed to reduce disparities in access to appropriate eye care.

Body mass index and dietary intake among Head Start children and caregivers

BACKGROUND

The US Head Start program serves low-income preschoolers and their caregivers and provides an opportunity for assessment and intervention on obesity. We sought to determine the prevalence of obesity among children and their caregivers and to identify variables that are associated with child body mass index (BMI) z scores and caregiver BMI.

DESIGN/SETTING

Cross-sectional data on diet and BMI from 770 caregiver-child dyads recruited from 57 Head Start centers in Alabama and Texas.

METHODS

Height and weight of each caregiver and child were measured using standardized protocols. Dietary intakes of caregiver-child dyads were collected using three 24-hour dietary recalls and Block food frequency questionnaires. Data were collected between September 2004 and November 2005. The larger Food Pyramid categories were divided into 17 food consumption groups and tested for their association with child BMI z scores. Analysis of variance was used to test if food groups were significantly associated with child BMI z score.

RESULTS

The prevalence of obesity among children was 18.4%, 24.3%, and 37.3% among black, Hispanic, and white children, respectively (P<0.0001), whereas it was 58.3%, 41.4%, and 41.6% among black, Hispanic, and white caregivers, respectively (P<0.0001). Child BMI z scores and caregiver BMIs were correlated (r=0.16, P<0.0001). In multivariable models, children were 1.90 (95% confidence interval 1.31-2.74) times more likely to have BMI ≥95th percentile if their caregiver was obese. Five variables (fruits, unsweetened beverages, low-fat dairy, race, and caregiver's BMI) were significantly associated with child BMI z scores. Fruits were inversely related, whereas unsweetened beverages, low-fat dairy, and caregiver's BMI were positively associated with child BMI z score (P<0.03). Compared to whites, black and Hispanic children had lower BMI z scores (P<0.05).

CONCLUSIONS

The high prevalence of obesity in this population together with the observed inverse association between fruit consumption and BMI, if replicated in other studies, suggests that interventions that promote fruit consumption could have beneficial effects on child BMI.

Effect of weight loss on urinary incontinence in overweight and obese women: results at 12 and 18 months

PURPOSE

Initial weight loss improves urinary incontinence in overweight and obese women. In this study we examined the longer term effects of a weight loss intervention on urinary incontinence.

MATERIALS AND METHODS

Overweight and obese women (mean +/- SD age 53 +/- 10 years) with 10 or more urinary incontinence episodes weekly were randomized to an 18-month behavioral weight loss intervention (226) or control group (112). Outcome measures were collected at 12 and 18 months.

RESULTS

At baseline women had a mean body mass index of 36 +/- 6 kg/m(2) and reported a mean of 24 +/- 18 incontinence episodes weekly. Of the patients 86% completed 18-month measurements. The percent weight loss in the intervention group averaged 8.0%, 7.5% and 5.5% at 6, 12 and 18 months, respectively, vs approximately 1.5% in the control group (all values p <0.001). Compared with controls at 12 months the intervention group reported a greater percent reduction in weekly stress urinary incontinence episodes (65% vs 47%, p <0.001), and a greater proportion achieved at least a 70% decrease in weekly total and stress urinary incontinence episodes. At 18 months a greater proportion of women in the weight loss intervention group had more than 70% improvement in urge incontinence episodes but there were no significant differences between the groups for stress or total urinary incontinence. The intervention group also reported greater satisfaction with changes in urinary incontinence than the control group at 6, 12 and 18 months.

CONCLUSIONS

Weight loss intervention reduced the frequency of stress incontinence episodes through 12 months and improved patient satisfaction with changes in incontinence through 18 months. Improving weight loss maintenance may provide longer term benefits for urinary incontinence.

The role of European genetic admixture in the etiology of the insulin resistance syndrome in children: are the effects mediated by fat accumulation?

OBJECTIVES

To evaluate the contribution of European genetic admixture (EUADM) to insulin resistance syndrome (IRS) in a multiethnic sample of children age 7-12 years, and to explore whether body fat affects this relationship.

STUDY DESIGN

Anthropometric measurements and blood pressure were assessed in 243 children. After an overnight fast, an intravenous glucose tolerance test was conducted, and measures of fasting insulin/glucose, lipids, insulin sensitivity (SI), and acute insulin response to glucose (AIRg) were obtained. The proportion of EUADM was determined by maximum likelihood estimation using 140 ancestry informative markers. Subjects were stratified into tertiles according to the proportion of EUADM for analyses. Subjects were categorized as lean or obese using body fat percentage cutpoints (25% in boys, 30% in girls).

RESULTS

Among lean subjects (72%), the tertile representing the greatest proportion of EUADM was associated with higher SI (P<.001) and serum glucose (P<.05) and lower insulin (P<.05), AIRg (P<.001), high-density lipoprotein cholesterol (P=.05), and blood pressure (P<.05). However, among obese subjects, EUADM was associated only with SI (P<.05).

CONCLUSIONS

Our results suggest that population differences in IRS likely have a genetic component, but that the influence of genetic background may be masked by obesity.

Fruit and vegetable pricing by demographic factors in the Birmingham, Alabama, metropolitan area, 2004-2005

INTRODUCTION

Fruit and vegetable cost may influence consumption. Because the contextual environment influences food outlet type and availability, we wanted to determine whether neighborhood demographics were associated with prices of fruits and vegetables.

METHODS

We surveyed 44 grocery stores in the Birmingham, Alabama, metropolitan area to determine prices of 20 fruits and vegetables. Stores were geocoded and linked to the corresponding Census 2000 block group to obtain data for the independent variables - percentage African American, percentage with at least a high school diploma, and percentage of households below the poverty level. We conducted multiple linear regressions to estimate these predictors for each fruit and vegetable's mean price per serving during 2 seasons (fall/winter 2004, spring/summer 2005).

RESULTS

In the fall, we found no significant relationships between the predictors and prices of any fruits and vegetables in the survey. In the spring, the percentage who had at least a high school diploma was a predictor of price per serving for potatoes (beta = 0.001, P = .046).

CONCLUSION

Neighborhood demographics have little consistent influence on fruit and vegetable prices in Birmingham, Alabama, which may be a function of grocery store density, transportation patterns, and shopping patterns. The regional setting of the food environment has implications for food availability, variety, and price.

Threshold for effects of vitamin D deficiency on glucose metabolism in obese female African-American adolescents

CONTEXT

Vitamin D status can influence insulin resistance.

OBJECTIVE

The aim of the study was to determine the prevalence of vitamin D deficiency in obese African-American (AA) adolescent females in a southeastern latitude and to determine the relationship of 25-hydroxyvitamin D [25(OH)D] with insulin and glucose dynamics.

DESIGN

We conducted a cross-sectional study in a University Children's Hospital.

METHODS

Serum 25(OH)D, fasting glucose, PTH, serum calcium, serum lipids, serum transaminases, and C-reactive protein were assessed. Indices of insulin sensitivity and resistance were determined from an oral glucose tolerance test. Subjects were classified as vitamin D deficient or sufficient, based on the traditional vitamin D deficiency definition [serum 25(OH)D <20 ng/ml] and also by a lower 25(OH)D cut-point of 15 ng/ml or less.

RESULTS

A total of 51 AA adolescent females (body mass index, 43.3 +/- 9.9 kg/m(2); age, 14 +/- 2 yr) were studied. Serum 25(OH)D concentrations were 20 ng/ml or less in 78.4% and 15 ng/ml or less in 60.8% of subjects. There were no significant group differences in the metabolic outcomes when subjects were classified using the traditional vitamin D deficiency definition. The Matsuda index of insulin sensitivity was significantly lower (P = 0.02), and insulin area under the curve was significantly higher (P = 0.04) in subjects with 25(OH)D concentrations of 15 ng/ml or less vs. those with higher concentrations.

CONCLUSIONS

Vitamin D deficiency is highly prevalent in obese, AA female adolescents and may promote insulin resistance. Our data suggest that a 25(OH)D concentration of 15 ng/ml or less may be the threshold by which vitamin D deficiency confers negative effects on insulin sensitivity.

Influences of physical and social neighborhood environments on children's physical activity and obesity

OBJECTIVES

We investigated the association between physical and social neighborhood environments and fifth-grade students' physical activity and obesity.

METHODS

We collected data on 650 children and their primary caregivers during phase 1 of Healthy Passages, a multisite, community-based, cross-sectional study of health risk behaviors and health outcomes in children. We conducted independent systematic neighborhood observations to measure neighborhood physical characteristics, and we analyzed survey data on social processes. We modeled children's physical activity and obesity status with structural equation models that included latent variables for the physical and social environments.

RESULTS

After we controlled for children's sociodemographic factors, we found that a favorable social environment was positively associated with several measures of physical activity and that physical activity was negatively associated with obesity in these children. Physical environment was not significantly associated with physical activity.

CONCLUSIONS

Our findings suggest that neighborhood social factors as well as the physical environment should be considered in the development of health policy and interventions to reduce childhood obesity.

Weight loss to treat urinary incontinence in overweight and obese women

BACKGROUND

Obesity is an established and modifiable risk factor for urinary incontinence, but conclusive evidence for a beneficial effect of weight loss on urinary incontinence is lacking.

METHODS

We randomly assigned 338 overweight and obese women with at least 10 urinary-incontinence episodes per week to an intensive 6-month weight-loss program that included diet, exercise, and behavior modification (226 patients) or to a structured education program (112 patients).

RESULTS

The mean (+/-SD) age of the participants was 53+/-11 years. The body-mass index (BMI) (the weight in kilograms divided by the square of the height in meters) and the weekly number of incontinence episodes as recorded in a 7-day diary of voiding were similar in the intervention group and the control group at baseline (BMI, 36+/-6 and 36+/-5, respectively; incontinence episodes, 24+/-18 and 24+/-16, respectively). The women in the intervention group had a mean weight loss of 8.0% (7.8 kg), as compared with 1.6% (1.5 kg) in the control group (P<0.001). After 6 months, the mean weekly number of incontinence episodes decreased by 47% in the intervention group, as compared with 28% in the control group (P=0.01). As compared with the control group, the intervention group had a greater decrease in the frequency of stress-incontinence episodes (P=0.02), but not of urge-incontinence episodes (P=0.14). A higher proportion of the intervention group than of the control group had a clinically relevant reduction of 70% or more in the frequency of all incontinence episodes (P<0.001), stress-incontinence episodes (P=0.009), and urge-incontinence episodes (P=0.04).

CONCLUSIONS

A 6-month behavioral intervention targeting weight loss reduced the frequency of self-reported urinary-incontinence episodes among overweight and obese women as compared with a control group. A decrease in urinary incontinence may be another benefit among the extensive health improvements associated with moderate weight reduction. (ClinicalTrials.gov number, NCT00091988.)

The impact of cost on the availability of fruits and vegetables in the homes of schoolchildren in Birmingham, Alabama

OBJECTIVES

Fruit and vegetable cost is a presumed barrier to intake. We sought to determine whether fruit and vegetable cost and consumers' race and income would predict availability of fruits and vegetables in homes of schoolchildren in the Birmingham, Ala, area.

METHODS

Data on availability of 27 fruit and vegetable items were obtained from homes of 1355 children (32% African American) in the Birmingham area. Fruit and vegetable costs were obtained from the US Department of Agriculture. We used discrete choice analysis with the dependent variable represented as presence or absence of the fruit or vegetable item. Explanatory variables included fruit and vegetable price per serving; child's gender, race, and age; and parent's body mass index and income.

RESULTS

Higher cost was inversely related to fruit and vegetable availability. Higher income, African American race, and female gender were positively related to availability. Cost per serving was stratified into 3 categories-low, medium, and high. Relative to low-cost items, only high-cost items decreased the odds of availability significantly.

CONCLUSIONS

Fruit and vegetable cost does impact availability and has the greatest impact for high-cost items. Although cost was inversely related to availability, African Americans reported higher fruit and vegetable availability than Whites. Additional studies are needed to determine whether food items of lower nutritive value and comparable cost impact availability.

Prevalence of obesity in the United States

Obesity is a major public health problem in the United States. Data on measured heights and weights indicates that the prevalence of obesity has significantly increased among the US population over the past 30 years. Data collected from 1999 to 2002 estimates that nearly 1/3 of adults are obese (27.6% of men and 33.2% of women) and one in six children and adolescents is overweight. Increased prevalence of excessive weight is noted among all age, gender and racial/ethnic groups; however, disparities exist. There is a need for further research to better understand why these increases have occurred, why the observed disparities exist and how to reverse these trends.

Phosphatidylcholine-rich acceptors, but not native HDL or its apolipoproteins, mobilize cholesterol from cholesterol-rich insoluble components of human atherosclerotic plaques

To examine the potential of high density lipoproteins (HDL) to ameliorate atherosclerotic plaques in vivo, we examined the ability of native HDL, lipid-free HDL apolipoproteins (apo HDL), cholesterol-free discoidal reconstituted HDL (R-HDL) comprised of apo HDL and phosphatidylcholine (PC) and PC liposomes to release cholesterol from cholesterol-rich insoluble components of plaques (ICP) isolated from atherosclerotic human aorta. Isolated ICP had a free cholesterol (FC) to phospholipid (PL) mass ratio (0.8-3.1) and a sphingomyelin (SPM) to PC mass ratio (1.2-4.2) that exceeded those of plasma membranes of cultured cells. Surprisingly, native HDL and its apolipoproteins were not able to release cholesterol from ICP. However, R-HDL and PC liposomes were effectively released cholesterol from ICP. The release of ICP cholesterol by R-HDL was dose-dependent and accompanied by the transfer of > 8 x more PC in the reverse direction (i.e., from R-HDL to ICP), resulting in a marked enrichment of ICP with PC. Compared to R-HDL, PC liposomes were significantly less effective in releasing cholesterol from ICP but were somewhat more effective in enriching ICP with PC. Native HDL was minimally effective in enriching ICP with PC, but became effective after prior in vitro enrichment of HDL with PC from multilamellar PC liposomes. The enrichment of ICP with PC resulted in the dissolution of cholesterol crystals on ICP and allowed the removal of ICP cholesterol by apo HDL and plasma. Our study revealed that the removal of cholesterol from ICP in vivo will be possible through a change in the level, composition, and physical state of ICP lipids mediated by PC-enriched HDL.

Contribution of postprandial lipemia to the dietary fat-mediated changes in endogenous lipoprotein-cholesterol concentrations in humans

BACKGROUND

Dietary fats alter LDL and HDL cholesterol while serving as precursors of postprandial triacylglycerol-rich lipoproteins (TRLs).

OBJECTIVE

We hypothesized that the saturated fatty acid (SFA)-mediated increase and the polyunsaturated fatty acid (PUFA)-mediated decrease in endogenous lipoprotein cholesterol are promoted by postprandial TRLs.

DESIGN

We performed a 16-d crossover diet study to examine the effect of PUFA-rich [ratio of PUFAs to SFAs (P:S) = 2.0] and SFA-rich (P:S = 0.25) diets on fasting and postprandial plasma lipid and lipoprotein-cholesterol concentrations in 16 normolipidemic subjects.

RESULTS

Fasting plasma cholesterol decreased significantly after a PUFA-rich diet because of a decrease in LDL (-12.3%; P < 0.05) and HDL (-3.8%; NS), but did not change after an SFA-rich diet. The appearance of postprandial TRLs in plasma at 4 h was linked to a significant lowering of both LDL (-7.4%) and HDL (-4.8%) after a PUFA-rich diet; no such effect was observed after the SFA-rich diet. At 7 h, LDL and HDL cholesterol returned to near fasting concentrations without postprandial TRL accumulation after a PUFA-rich diet but with a significant postprandial TRL accumulation after an SFA-rich diet. Thus, the in vivo postprandial clearance of cholesterol in LDL+HDL was greater after a PUFA-rich diet than after an SFA-rich diet. The appearance of postprandial TRLs in plasma increased the cholesteryl ester transfer protein-mediated transfer of cholesteryl ester from LDL+HDL to TRLs in vitro without a significant influence from dietary fat.

CONCLUSION

Dietary fat-mediated alterations in the rate of hepatic removal of postprandial TRLs, which carry cholesterol accepted from LDL+HDL via cholesteryl ester transfer protein in vivo, may contribute to the dietary fat-mediated change in endogenous lipoprotein cholesterol.

Postprandial chylomicrons

We examined whether postprandial (PP) chylomicrons (CMs) can serve as vehicles for transporting cholesterol from endogenous cholesterol-rich lipoprotein (LDL+HDL) fractions and cell membranes to the liver via lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) activities. During incubation of fresh fasting and PP plasma containing [(3)H]cholesteryl ester (CE)-labeled LDL+HDL, both CMs and VLDL served as acceptors of [(3)H]CE or cholesterol from LDL+HDL. The presence of CMs in PP plasma suppressed the ability of VLDL to accept [(3)H]CE from LDL+HDL. In reconstituted plasma containing an equivalent amount of triglycerides from isolated VLDL or CMs, a CM particle was about 40 times more potent than a VLDL particle in accepting [(3)H]CE or cholesterol from LDL+HDLs. When incubated with red blood cells (RBCs) as a source for cell membrane cholesterol, the cholesterol content of CMs, VLDL, LDL, and HDL in PP plasma increased by 485%, 74%, 13%, and 30%, respectively, via LCAT and CETP activities. The presence of CMs in plasma suppressed the ability of endogenous lipoproteins to accept cholesterol from RBCs. Our data suggest that PP CMs may play an important role in promoting reverse cholesterol transport in vivo by serving as the preferred ultimate vehicle for transporting cholesterol released from cell membranes to the liver via LCAT and CETP.

Alcohol-mediated enhancement of postprandial lipemia: a contributing factor to an increase in plasma HDL and a decrease in risk of cardiovascular disease

BACKGROUND

Moderate alcohol consumption increases plasma HDL and lowers cardiovascular disease risk while transiently enhancing postprandial lipemia.

OBJECTIVE

We hypothesized that the alcohol-mediated increase in postprandial triacylglycerol-rich lipoproteins (TRLs) and their clearance elevate HDL cholesterol and reverse cholesterol transport.

DESIGN

We determined the effect in normolipidemic humans (n = 14) of postprandial lipemia produced 4 h after a test meal (M) or a test meal + 0.5 g alcohol/kg body wt (M+A) on postprandial changes in plasma lipids and on the balance of cholesterol between TRL and the cholesterol-rich LDL and HDL fractions (CRL) or red blood cells (RBCs) in fresh and incubated plasma or blood.

RESULTS

Postprandial lipemia after the M and M+A test meals caused a 56% and 89% increase in plasma triacylglycerol, a 30% and 74% increase in TRL cholesterol, and a 3.8% and 6.6% decrease in CRL cholesterol, respectively. In vitro reaction of endogenous lecithin:cholesterol acyltransferase (EC 2.3.1.43) and cholesteryl ester transfer proteins via incubation of fasting plasma samples and postprandial M and M+A plasma samples for 16 h increased TRL cholesterol by 22.8% (0.08 mmol/L), 32.6% (0.16 mmol/L), and 45.8% (0.28 mmol/L) in plasma and by 71.1% (0.27 mmol/L), 89.4% (0.45 mmol/L), and 112.5% (0.70 mmol/L) in RBC-enriched blood, respectively. After the in vitro lipolysis of TRL, the elevation of HDL cholesterol in postprandial M+A plasma, but not in postprandial M plasma, was significantly greater than in fasting plasma.

CONCLUSION

The alcohol-mediated increase in postprandial TRL flux and the hepatic removal of postprandial TRL after the acceptance of cholesterol from CRL and cell membranes contribute to increased HDL cholesterol and enhancement of reverse cholesterol transport in humans.

Contribution of insulin secretion and clearance to glucose-induced insulin concentration in african-american and caucasian children

Relative to Caucasians (C), African-American (AA) children and adults have lower indices of insulin sensitivity (S(i)) and a higher acute insulin response to glucose (AIR(g)). Among AA children, AIR(g) is greater than that which would be predicted based on lower S(i). The objectives of the present study were 1) to determine whether insulin secretory parameters differ in AA vs. C children and adolescents using C-peptide modeling, 2) to determine whether hepatic insulin extraction differs with ethnicity/race using the C-peptide to insulin molar ratio, and 3) to determine whether the relatively greater AIR(g) among African-Americans is due to greater insulin secretion or lesser clearance. Subjects (n = 76) were AA and C children (mean age, approximately 11 yr). A 3-h tolbutamide-modified iv glucose tolerance test and minimal modeling were used to determine S(i) and AIR(g). First phase C-peptide/insulin secretion and basal, first, and second phase beta-cell sensitivity to glucose were determined using C-peptide modeling with standard kinetic parameters developed in adults. The incremental C-peptide to insulin molar ratio over the 3-h test period, an index of hepatic insulin extraction, was calculated with the trapezoidal method. S(i) was lower and AIR(g) was higher in AA vs. C children. First phase C-peptide/insulin secretion and first phase beta-cell sensitivity to glucose were approximately 2-fold greater in AA vs. C children (P < 0.001); there were no between-group differences in basal or second phase beta-cell sensitivity to glucose. Hepatic insulin extraction was lower in AA vs. C (3.77 +/- 1.78% vs. 5.99 +/- 2.18%; P < 0.001). Multiple linear regression modeling indicated that first phase C-peptide/insulin secretion and hepatic insulin extraction contributed independently to AIR(g); however, it was only first phase C-peptide/insulin secretion that explained the significant independent contribution of ethnicity/race to AIR(g) after adjusting for S(i). The results of this study suggest that greater AIR(g) among AA is due to both greater insulin secretion and lesser hepatic insulin extraction, and that AIR(g) above that predicted based on lower S(i) is due to greater insulin secretion. The insulin secretion data await verification that the kinetic parameters used apply to children and AA.

In vitro production of beta-very low density lipoproteins and small, dense low density lipoproteins in mildly hypertriglyceridemic plasma: role of activities of lecithin:cholester acyltransferase, cholesterylester transfer proteins and lipoprotein lipase

As a model for the formation of beta-very low density lipoproteins (VLDL) and small, dense LDL by the intraplasma metabolic activities in vivo, lipoproteins in fresh plasma were interacted in vitro with endogenous lecithin:cholesterol acyltransferase (LCAT) and cholesterylester transfer proteins (CETP) and subsequently with purified lipoprotein lipase (LpL). The LCAT and CETP reactions in a mildly hypertriglyceridemic (HTG) plasma at 37 degrees C for 18 h resulted in (1) esterification of about 45% plasma unesterified cholesterol (UC), (2) a marked increase in cholesterylester (CE) (+129%) and a decrease in triglyceride (TG) (-45%) in VLDL, and (3) a marked increase of TG (+ 341%) with a small net decrease of CE (-3.6%) in LDL, causing a significant alteration in the TG/CE of VLDL (from 8.0 to 1.9) and of LDL (from 0.20 to 0.93). The LDL in LCAT and CETP-reacted plasma is larger and more buoyant than that in control plasma. In vitro lipolysis of control and LCAT and CETP-reacted plasma by LpL, which hydrolyzed >90% of VLDL-TG and about 50-60% of LDL-TG, converted most of VLDL in control plasma (>85%) but less than half (40%) of VLDL in LCAT and CETP-reacted plasma into the IDL-LDL density fraction and transformed the large, buoyant LDL in the LCAT and CETP-reacted plasma into particles smaller and denser than those in the control plasma. The remnants that accumulated in the VLDL density region of the postlipolysis LCAT and CETP-reacted plasma contained apo B-100 and E but little or no detectable apo Cs and consisted of particles having pre-beta and beta-electrophoretic mobilities. The inhibition of LCAT during incubation of plasma, which lessened the extent of alteration in VLDL and LDL core lipids, increased the extent of lipolytic removal of VLDL from the VLDL density region but lowered the extent of alteration in the size and density of LDL. The LCAT, CETP and/or LpL-mediated alterations in the density of LDL in normolipidemic fasting plasma were less pronounced than that in mildly HTG plasma, but they became highly pronounced upon increase of its TG-rich lipoprotein level by the addition of preisolated VLDL or by the induction of postprandial lipemia. Although the effect of LCAT, CETP and LpL reactions in non-circulating plasma in vitro may be different from that in vivo, the above data suggests that the plasma TG-rich lipoprotein level and the extent of intraplasma LCAT, CETP, LpL and likely hepatic lipase (HL) reactions in vivo may play a role in determining the LDL phenotype.

Potencies of lipoproteins in fasting and postprandial plasma to accept additional cholesterol molecules released from cell membranes

To investigate the role of various lipoproteins in plasma to promote cholesterol efflux from cell membranes, potencies of lipoproteins in normolipidemic fasting and postprandial (PP) plasmas to accept additional cholesterol molecules from cell membranes were determined. We used red blood cells (RBCs) and lipoproteins in fresh blood as donors and acceptors of cell membrane cholesterol, respectively. When fresh fasting plasma (n=24) containing active lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer proteins (CETP) was incubated with a 3-fold excess of autologous RBCs at 37 degrees C for 18 hours, plasma cholesterol levels increased by 19.6% (38.5+/-14.2 mg/dL) owing to an exclusive increase in the CE level. Very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL) fractions retained 48.1%, 26.3%, and 25.6% of the net cholesterol mass increase in fasting plasma, resulting in 91%, 8%, and 21% increases in their cholesterol contents, respectively. The PP plasma was 1.3-fold more potent than fasting plasma in promoting cholesterol efflux from RBCs by associating excess cholesterol with chylomicrons, resulting in a 356% increase in the cholesterol content of chylomicrons. These increases in lipoprotein cholesterol content indicate that chylomicrons were about 3.9x, 44x, and 17x more potent than fasting VLDL, LDL, and HDL, respectively, in accepting additional cholesterol molecules released from RBCs. The capacity of PP plasma to promote cholesterol efflux from RBCs was significantly correlated with plasma cholesterol levels (r=0.60, P<0.005), triglycerides (r=0.68, P<0.001), chylomicrons (r=0.90, P<0.001), VLDL (r=0.65, P<0.001), and LDL (r=0.47, P<0.025) but not with the levels of HDL (r= -0.34, P<0.20). In fasting plasma containing a low level of VLDL and HDL, isolated chylomicrons supplemented to the plasma were approximately 9x more potent than HDL in boosting the capacity of plasma to promote cholesterol efflux from RBCs. This study indicates that chylomicrons in PP plasma are the most potent ultimate acceptors of cholesterol released from cell membranes and that a low HDL level is not a factor that limits the ability of PP plasma to promote cholesterol efflux from cell membranes. Our data obtained from an in-vitro system suggest that PP chylomicrons may play a major role in promoting reverse cholesterol transport in vivo, since the transfer of cholesterol from cell membranes to chylomicrons will lead to the rapid removal of this cholesterol by the liver. HDL in vivo may promote reverse cholesterol transport by enhancing the rapid removal of chylomicrons from the circulation, since the rate of clearance of chylomicrons is positively correlated with the HDL level in plasma.

Recruitment issues in school-based research: lessons learned from the High 5 Alabama Project

School-based research requires a multi-level recruitment process to ensure an adequate sample. This article describes the High 5 Alabama recruitment experience at four levels; district, school, classroom and individual. One hundred percent of 28 schools across three districts and 108 classroom teachers contacted agreed to participate. Moderate success (69%) at the individual level, which required active parental consent for the student and parent to participate, resulted in 1,698 student/parent participants. An examination of differences between participants and nonparticipants revealed under-representation of a subsample of the population in the project sample. Suggestions obtained from project staff and teachers intended to enhance future school-based recruitment strategies include enlistment of a district advocate; meeting with teachers to solicit support; using incentives with students and teachers; direct contact with parents; having teachers keep rosters of students returning consent forms; and tailoring recruitment strategies for specific subpopulations.

Effects of diet and sexual maturation on low-density lipoprotein cholesterol during puberty: the Dietary Intervention Study in Children (DISC)

BACKGROUND

The Dietary Intervention Study in Children (DISC) is a multicenter, randomized, controlled clinical trial designed to examine the efficacy and safety of a dietary intervention to reduce serum LDL cholesterol (LDL-C) in children with elevated LDL-C.

METHODS AND RESULTS

The effects of dietary intake of fat and cholesterol and of sexual maturation and body mass index (BMI) on LDL-C were examined in a 3-year longitudinal study of 663 boys and girls (age 8 to 10 years at baseline) with elevated LDL-C levels. Multiple linear regression was used to predict LDL-C at 3 years. For boys, LDL-C decreased by 0.018 mmol/L for each 10 mg/4.2 MJ decrease in dietary cholesterol (P<.05). For girls, no single nutrient was significant in the model, but a treatment group effect was evident (P<.05). In both sexes, BMI at 3 years and LDL-C at baseline were significant and positive predictors of LDL-C levels. In boys, the average LDL-C level was 0.603 mmol/L lower at Tanner stage 4+ than at Tanner stage 1 (P<.01). In girls, the average LDL-C level was 0.274 mmol/L lower at Tanner stage 4+ than at Tanner stage 1 (P<.05).

CONCLUSIONS

In pubertal children, sexual maturation, BMI, dietary intervention (in girls), and dietary cholesterol (in boys) were significant in determining LDL-C. Sexual maturation was the factor associated with the greatest difference in LDL-C. Clinicians screening for dyslipidemia or following dyslipidemic children should be aware of the powerful effects of pubertal change on measurements of lipoproteins.

Community collaboration: prevention and control of tuberculosis in a homeless shelter

An urban shelter in Charleston, South Carolina developed and began a tuberculosis (TB) prevention and control plan that addressed the priorities recommended by the Centers for Disease Control and Prevention. After an increase in TB in the shelter in 1992, the local health department, the homeless clinic nurse practitioners, and Medical University of South Carolina College of Nursing faculty and students collaborated with the shelter staff to provide initial mass screenings for contact investigation. They also developed and implemented new policies and procedures for an ongoing TB prevention and control program. The new policies required that guests obtain screening for TB within 7 days of arrival at the shelter and every 6 months thereafter. Also, a public health nurse began providing directly observed therapy twice weekly at the shelter. Of the initial 22 persons who started TB preventive therapy in 1993, 17 (77%) completed therapy. The clinic nurse practitioners, nursing students, and public health nurses had important and defined roles in the mass-screening process, case identification and treatment, policy development and implementation, health education, and establishing methods of communication between the shelter, clinic, and health department. An ongoing health care community collaborative effort may successfully reduce tuberculosis disease in a homeless shelter population.