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Biomedical subjects

Robert H Glew

Publications and source records attributed to Robert H Glew.

At least 19 recordsLinked to original sources

Trans fatty acids and conjugated linoleic acids in the milk of urban women and nomadic Fulani of northern Nigeria.

BACKGROUND: Trans fatty acids (TFAs) and conjugated linoleic acids (CLAs) are present in dairy products and human milk and can have detrimental and beneficial effects in humans. The content of TFAs and CLAs in milk is determined largely by the diet of the mother. METHODS: We compared the proportions of TFAs and CLAs in the milk of rural Fulani in northern Nigeria who consume dairy products to that of women living in an urban center who consume little in the way of dairy products. Lactating Fulani women (n=41) and women residing in the city of Jos, Nigeria (n=41) were recruited into the study. We predicted that the milk of the Fulani pastoralists would contain higher amounts of TFAs and CLAs compared to their urban counterparts. RESULTS: The mean total TFA proportions for the Fulani and urban women were 0.22% and 0.34%, respectively, and were not significantly different. The percentages of CLAs in milk fat were not different between rural and urban women (0.16% vs 0.14%). These TFA and CLA values were 4- to 10-fold lower than for milk of women elsewhere in the world. CONCLUSIONS: The percentages of TFAs and CLAs in milk were not different between rural and urban dwellers in northern Nigeria whose diets differ greatly in the amounts of dairy products they contain. However, the fact that the percentages of TFAs and CLAs in the milk of Nigerian women were much lower than the percentages reported from other parts of the world may have implications for the long-term growth and development of infants in the northern Nigeria and elsewhere in the Western Sahel.

Adult↗

Nutrient content of four edible wild plants from west Africa.

Non-cereal plant foods in the Western Sahel of Africa contribute significantly to the diets of local residents, especially during periods of grain shortages. In this paper, we analyze four such plant foods including diyan kwakwa (nut of coconut palm, Cocos nucifera L.), muricin giginya (young shoot of Borassus aethiopum), tsamiya biri (fruit of the tree, Tamarindus indica), and yari (a mixture of lichens, mainly Rimelia reticulate) that grows on ebony trees (Diospyros mespiliformis). They were analyzed for their content of amino acids, fatty acids, and minerals. Although diyan kwakwa contained the highest protein content (27.1%), its protein quality fell below the WHO standard in 3 of 8 essential amino acid categories. Yari and muricin giginya contained moderate levels of good quality protein. Only diyan kwakwa contained calorically significant amount of total fatty acid (24.7%); however, none of the plants contained useful amounts of the essential fatty acids, linoleic acid, or alpha-linolenic acid. All four plants contained useful amounts of zinc (> 12 microg/g dry weight), while yari contained the most calcium (14.7 mg/g dry weight) and iron (1.41 mg/g), and diyan kwakwa the most copper. All the four plant foods contained lesser amounts of magnesium, molybdenum, or selenium. These data indicate that the four plants contain useful amounts of various essential nutrients that could supplement the diets of populations inhabiting the Western Sahel.

Africa, Western↗

Effect of Norplant contraceptive on the bones of Nigerian women as assessed by quantitative ultrasound and serum markers of bone turnover.

Levonorgestrel is a commonly used progestin-only contraceptive that is available as subdermal (Norplant) and intrauterine implants. Other progestin-only contraceptives such as injectable medroxyprogeterone acetate have been shown to decrease bone mineral density in long-term users. We used calcaneal ultrasound to compare the bone quality of Nigerian women between 25 and 50 years of age who had Norplant implants for 1-4 years to that of women who were not using any form of hormonal contraceptive. The mean stiffness index of women who had Norplant implants for as long as 4 years was not significantly different from that of controls. However, serum markers of bone turnover were significantly decreased in women with Norplant implants compared to age-matched controls. Serum bone-specific alkaline phosphatase was significantly decreased in subjects with Norplant implants for 1 year (13.7+/-6.0 vs. 23.0 U/L for controls, p = .001) and serum NTx was significantly decreased in subjects with implants for 3 years (10.6+/-4.9 vs. 17.6+/-7.7 bone collagen equivalents per liter for controls, p < .001). We conclude that although levonorgestrel contraceptive decreased overall bone turnover, it had no deleterious effect on the bone quality of women using Norplant implants for up to 4 years.

Adult↗

Lack of precision of indirect estimates of body water affects urea kinetic analysis in chronic peritoneal dialysis.

To test the precision of estimates of body water and urea clearance in peritoneal dialysis (PD), we compared, in 925 PD patients who underwent formal urea kinetics studies, estimates of V and Kt/V urea obtained by the use of the Watson, Hume, and Sahlgrenska anthropometric formulas and two novel formulas, one (Vcreat) computed using fat-free mass (FFM) estimated from creatinine kinetics as 0.73 x FFMcreat, and the other (VBMI) calculated as 0.73 x FFM(BMI) where FFM(BMI) was obtained by the Gallagher formula, which estimates body composition as a function of body mass index (BMI). Comparisons by twos were performed using the paired t-test and the Wilcoxon sign rank test with the Bonferroni correction for multiple (n=10) comparisons. The results for V (liters) were Watson, 36.7 +/- 7.1; Hume, 37.3 +/- 7.3; Sahlgrenska, 36.8 +/- 7.6; Vcreat, 32.2 +/- 9.8; and VBMP 37.2 +/- 7.8. With the exception of V(BMI) and V(Hume) which did not differ, all other values differed (p < 0.001) from one another regardless of whether a parametric or nonparametric comparison was performed. The results for weekly total Kt/V urea were Watson, 2.05 +/- 0.57; Hume, 2.03 +/- 0.57; Sahlgrenska, 2.06 +/- 0.59; from Vcreat 2.42 +/- 0.71; and from V(BMP) 2.03 +/- 0.58. All of those values differed from one another (p < 0.001) by both methods of comparison. Using cut-off values (1.50, 1.75, and 2.00) as indices of adequate total weekly Kt/V urea, the discrepancies between any two estimates by the five studied formulas varied in the range 1.1% - 34.2%. Despite numerically close mean values, estimates of V based on various anthropometric formulas differ substantially and cause substantial discrepancies in the classification of Kt/V urea as inadequate or adequate. This lack of precision, added to the known lack of accuracy of the estimates, confounds the interpretation of the clinical relevance of urea kinetic estimates in PD.

Body Composition↗

Characteristics of end stage renal disease diabetic patients in two countries with different socioeconomic conditions.

PURPOSE: To identify differences that may affect morbidity and mortality of type 2 diabetic patients reaching ESRD between countries with different socioeconomic conditions. METHODS: Comparison of clinical and laboratory features between 21 Nigerian (N) and 57 American patients (A) reaching ESRD over a 30 month period. RESULTS: Differences were noted in age at ESRD (N, 55.5+/-9.8; A, 64.5+/-9.6 years), duration of diabetes (N, 5.2+/-2.8, A: 14.9+/-4.9 years), body mass index (N, 24.5+/-4.1; A; 27.6+/-6.3 kg/m2), prevalence of left ventricular hypertrophy (N; 14%; A, 89%) and ischemic heart disease (N, 26%; A, 67%), blood pressure (N, [166.2+/-26.7]/[98.6+/-16.5] mmHg; A, [146.8+/-23.6]/[72.5+/-13.3] mmHg), creatinine clearance (N, 6.1+/-3.6; A, 14.8+/-3.5 ml/min), urine protein excretion (N, 1.2+/-0.7; A, 6.1+/-4.9 g/24-h), hematocrit (N, 28.0+/-6.0; A, 35.0+/-5.0%), serum glucose (N, 5.6+/-1.6; A, 10.5+/-5.5 mmol/l), and serum cholesterol (N, 5.32+/-2.57; A, 4.19+/-1.16 mmol/l) (all at P < or = 0.05). Differences were also found in the number of antihypertensive medications (N 1.4+/-0.6; A 2.4+/-1.2 per patient), and use of medications for diabetes (N 29%, A 79%), statins (N zero, A 61 %) and erythropoietin (N zero, A 39%). 72% of the A, but none of the N patients had a functional dialysis access prior to ESRD. CONCLUSIONS: Between A and N patients reaching ESRD, there are differences in clinical features and laboratory values that may affect morbidity, mortality and impact on the health care resources. These differences indicate areas where further studies that could assist in the planning for ESRD care in both Nigeria and USA are required.

Cross-Sectional Studies↗

Plasma and urinary free amino acid concentrations in preeclamptic women in northern Nigeria.

BACKGROUND: Preeclampsia/eclampsia is one of the major causes of maternal and fetal mortality in Nigeria and many other countries in sub-Saharan Africa. We determined if serum and urine concentrations of amino acids were abnormal in women with this disorder of pregnancy in Gombe, Nigeria. METHODS: Free amino acids were measured in serum and urine of women (ages, 15 to 40 years) with preeclampsia/eclampsia (n=37) and their pregnant age and gestational age matched controls (n=16). RESULTS: The concentrations of 19 of the 20 serum amino acids that are common in proteins were not significantly different between the control and preeclamptic groups. Phenylalanine was increased in the preeclamptic women compared to the controls (p<0.05); however, the difference between the two values was small (119 vs. 104 umol/l, respectively). The concentrations of urine free amino acids were indexed to urine creatinine (i.e., nmol/mg creatinine). Five amino acids were significantly elevated in the urine of preeclamptic patients vs. the control group: proline (100%, p<0.05), the branched amino acids, valine (80%, p<0.05), leucine (61%, p<0.05), isoleucine (49%, p=0.01), and methionine (52%, p<0.005). On the other hand, the concentrations of a nutritionally non-essential amino acid, glycine (p=0.01), and an essential amino acid, histidine (p=0.01), were both reduced by about one-third in the urine of the preeclamptic women. CONCLUSIONS: Our findings indicate that there are disturbances in urinary amino acid excretion but not in the serum amino acid profile in the preeclamptic patients. The degree of aminoaciduria is probably not sufficient to significantly affect overall nitrogen balance or precipitate a deficiency of one or more of the essential amino acids.

Adult↗

High-density lipoprotein and homocysteine levels correlate inversely in preeclamptic women in northern Nigeria.

BACKGROUND: Preeclampsia/eclampsia is one of the most common complications of pregnancy. It is a cause of high morbidity for both mother and fetus, especially in developing countries. In a recent survey conducted in Gombe, Nigeria, eclampsia was found to be a major cause of maternal mortality (24.2%), second only to obstetric hemorrhage (27.1%). Previous studies have produced contradictory findings regarding total homocysteine (tHcy) levels in women with preeclampsia/eclampsia and there is little information about the relationship between particular serum lipids and tHcy. The objective of this study in Gombe was to compare the levels of serum lipids and homocysteine in healthy pregnant women and women with preeclampsia/eclampsia in Nigeria. METHODS: The experimental subjects included 43 women with preeclampsia/eclampsia and 130 healthy pregnant women served as controls. The criteria for preeclampsia/eclampsia included the following: hypertension (blood pressure > 140/90 mmHg), total protein (> 190 mg/g creatinine), and edema. Blood sera obtained from patients and controls attending the prenatal clinics at the Specialist Hospital and the Federal Medical Center in Gombe were analyzed for tHcy, total cholesterol, triglycerides, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, antioxidant capacity, folate, and vitamin B-12. RESULTS: The mean tHcy concentration for the preeclamptic/eclamptic women was greater than that of the controls (10.1 vs. 8.4 micromol/l, respectively, p = 0.01). The mean concentrations of LDL-cholesterol and triacylglycerols were not different between the two groups. However, the mean HDL-cholesterol level was higher in the healthy pregnant women compared with the preeclamptic/eclamptic women (1.64 vs. 1.42 mmol/l, respectively, p = 0.02). The HDL-cholesterol concentration was correlated inversely with the tHcy concentration (p = 0.001, r = 0.51). Total homocysteine was not linked with either serum folate or vitamin B-12. CONCLUSIONS: These results show that preeclampsia/eclampsia is associated with increased tHcy levels and that HDL levels are depressed in Nigerian women with this hypertensive, pregnancy associated disorder.

Adult↗

Pulmonary function of herdsmen.

OBJECTIVE: To determine whether the pulmonary function deficit documented previously in Fulani children is also present in adult Fulani herdsmen in northern Nigeria. SUBJECTS AND METHODS: The subjects for this study consisted of adult Fulani men from the hamlet of Magama Gumau and adult non-Fulani men from the city of Jos. Age, height, weight, mid-arm circumference (MAC), triceps skin-fold thickness, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow during the middle half of the FVC maneuver (FEF25-75%), and peak expiratory flow rate (PEF) were measured. Body mass index (BMI) and FEV1/FVC were calculated for all subjects. Multiple regression analysis was performed to identify correlations between pulmonary function parameters and anthropometric variables. RESULTS: The 44 Fulani subjects and 28 urban subjects were well-matched for age and height. The Fulani men weighed significantly less than the urban men (58.5+/-9.4 versus 67.4+/-11.3 kg, p <0.001) and consequently had significantly lower BMI, MAC, and triceps skin-fold thickness. The only significant difference in pulmonary function parameters between the two groups was in FEV1/FVC (0.93+/-0.1 versus 0.85+/-0.1, p <0.001). Small but significant correlations were found between pulmonary function parameters and anthropometric variables for both study populations. CONCLUSIONS: The pulmonary function deficits documented previously in Fulani children and adolescents were not present in adult Fulani men. However, the observed elevation in FEV1/FVC in the rural Fulani men as compared to their urban counterparts, which is often seen in restrictive pulmonary patterns, deserves further study.

Adult↗

Abnormalities in the fatty-acid composition of the serum phospholipids of stroke patients.

The incidence of cardiovascular diseases, stroke, and myocardial infarction is increasing in sub-Saharan Africa. Since dietary polyunsaturated fatty acids (PUFA) are protective of the cardiovascular system in humans, we were interested in the question of the PUFA status of adults in northern Nigeria who had experienced a recent stroke. We collected blood from 21 consecutive admissions for stroke (15 male patients, mean age 39.3 years and six females, mean age 40.7 years) to the Federal Medical Centre in Gombe, Nigeria and analyzed the fatty-acid composition of the serum phospholipids. Blood was collected from 30 healthy controls for comparison. The contribution palmitic acid made to the fatty-acid total was greatly decreased in the phospholipids of the stroke patients (29.2% versus 37.2 %, p < 0.001). However, the phospholipids of the stroke patients had significantly higher percentages of 20-, 22-, and 24-carbon saturated fatty acids, as well as higher proportions of the omega-6 fatty-acid, arachidonic acid (11.4 versus 8.14%, p < 0.001), and the omega-3 fatty-acid, docosahexaenoic acid (3.21 versus 1.80%, p < 0.001). Using the percentages and melting points of the individual fatty acids, we estimated that the acyl chains of the serum phospholipids of the stroke patients had a lower mean melting point than the controls (27.8 versus 34.6 degrees C, p < 0.001). Assuming that serum phospholipids are surrogates for tissue phospholipids, we conclude that the tissue membranes of the stroke patients may be considerably more fluid than those of the controls.

Adult↗

Serum lipid profiles and homocysteine levels in adults with stroke or myocardial infarction in the town of Gombe in northern Nigeria.

While the incidence of infectious diseases has been on the decline in developing countries, the toll of cardiovascular diseases, including stroke and myocardial infarction, has been increasing. The impression of physicians in certain regions of the western Sahel, including the state of Gombe in northeastern Nigeria, is that macrovascular disease in the indigenous population is on the rise. This study was, therefore, undertaken to compare well-established risk factors for cardiovascular disease in a group of 53 men (n=34) and women (n=19) in the town of Gombe who had suffered a stroke or heart attack with the corresponding parameters in 48 age- and gender-matched healthy adults living in the same environment. The parameters of cardiovascular diseases considered were: overweight and obesity, blood pressure, lipid profiles, and homocysteine. While the male and female patients who had suffered stroke (n=48) or heart attack (n=5) were borderline hypertensive, their mean body mass index values were not different from the corresponding values of their control groups. Although the serum homocysteine levels of the patients and controls were not significantly different, 85% of the stroke patients had serum homocysteine levels greater than 10 microM. These high homocysteine levels could not be accounted for by sub-optimal folate or vitamin B 12 status. The serum levels of HDL-cholesterol and triglyceride were not significantly different between the male and female patients and their respective controls. However, the males, but not the females, with macrovascular disease had significantly higher levels of total cholesterol (161 vs 137 mg/dL, p=0.04) and LDL-cholesterol (91 vs 70 mg/dL, p=0.02). In addition, both female and male stroke/myocardial infarction patients exhibited an elevated LDL-cholesterol/HDL-cholesterol ratio. These results indicate that blood pressure and the LDL-cholesterol/HDL-cholesterol ratio are associated with stroke and myocardial infarction in adults in northern Nigeria, thereby creating potential opportunities for possible public-health interventions.

Case-Control Studies↗

Risk factors for cardiovascular disease and diet of urban and rural dwellers in northern Nigeria.

Over the last 30 years, cardiovascular diseases (CVDs), including stroke and myocardial infarction, have increased in developing countries. Serum lipids and diet of the Fulani, a rural Nigerian population, were previously studied. Despite their consumption of a diet rich in saturated fat, the overall blood lipid profiles of Fulani men and women are generally favourable. However, Fulani males in the same study had mean serum levels of homocysteine, an emerging risk factor for CVD, that exceeded the upper limit of the homocysteine reference range. The authors were interested in knowing if these findings in the Fulani nomads were representative of the biochemical parameters of CVD risk in other ethnic groups in the same region of Nigeria. To address this question, the nutrient content of diets of 55 men, aged 20-75 years, and 77 women, aged 20-70 years, who were inhabitants of a large urban centre in northern Nigeria, was assessed, and their serum levels of total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, and homocysteine were determined. These data were compared with those of the same rural Fulani population studied previously. Urban subjects consumed more calories than rural subjects (men: 2061 vs 1691 kcal; women: 1833 vs 1505 kcal) and had a significantly higher mean body mass index (BMI) and percentage of body fat than rural subjects. Both urban males and females had carbohydrate intakes that were greater than those of Fulani pastoralists (men: 56% vs 33% total calories; women: 51% vs 38% total calories), but had a significantly lower dietary intake of total fat and saturated fat (men: 36% vs 51% of total calories; women: 40% vs 51% of total calories). With the exception of HDL-cholesterol levels, which were significantly lower in the rural population, the blood lipid profiles of rural subjects were more favourable compared to those of urban subjects. Both urban and rural males had homocysteine levels above the upper limit of the reference range for healthy adults (urban males--12.7 micromol/L; rural males-15.2 micromol/L). The dietary intakes of folate and vitamin B12 were lower for rural Fulani subjects, and this was reflected in their significantly lower serum concentrations of these two vitamins. Results of this study suggest that, although the lipid profiles of urban and rural men and women in northern Nigeria indicate a relatively low risk for CVD, their elevated serum homocysteine levels are a cause for concern. The high homocysteine levels among rural men and women could be explained in part at least by their marginal status with respect to folate and vitamin B12.

Adult↗

Phase angle correlates with n-3 fatty acids and cholesterol in red cells of Nigerian children with sickle cell disease.

OBJECTIVE: To determine the cholesterol content and fatty acid composition of red cell membrane phospholipids (PL) of children with sickle cell disease (SCD) and to correlate these levels with whole body phase angle that is related to the integrity and function of cell membranes. STUDY DESIGN: Blood samples were obtained from 69 children with SCD and 72 healthy age- and gender-matched controls in Nigeria for the determination of the cholesterol content and proportions of fatty acids in red cell PL. Bioelectrical impedance analysis was used to obtain resistance (R) and reactance (Xc) from which phase angle was calculated as arctan Xc/R. Cholesterol (normalized to lipid phosphorus) and the proportions of individual fatty acids were correlated with phase angle. RESULTS: The proportions of palmitic (p < 0.001), stearic acid (p = 0.003) and cholesterol (p < 0.001) were significantly higher in the red cells of children with SCD, whereas the proportions of arachidonic acid and docosahexaenoic acid were reduced (p = 0.03 and < 0.001, respectively) compared to controls. The phase angle was inversely correlated with the proportions of palmitic acid (p = 0.03) and oleic acid (p < 0.001) and cholesterol (p = 0.003). Three n-3 polyunsaturated fatty acids-eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid- were positively correlated with phase angle (p < 0.001). CONCLUSIONS: The fatty acid composition and cholesterol content of tissue membranes in SCD correlate with the phase shift measured by bioelectrical impedance analysis. Phase angle measurements may provide a non-invasive method for monitoring interventions aimed at altering the lipid composition of membranes.

Journal Article↗

Estimates of body water, fat-free mass, and body fat in patients on peritoneal dialysis by anthropometric formulas.

BACKGROUND: Anthropometric formulas that are used to estimate body water in peritoneal dialysis patients can also be used to estimate fat-free mass and body fat. Evaluation of body composition by the anthropometric formulas rests on two assumptions: (1) fat contains no water, and (2) the water content of the fat-free mass is constant (72%). METHODS: We compared estimates of body water, fat-free mass, and body fat by anthropometric formulas to estimates employing dilution of tracer substances to measure body water and standard methods to analyze body composition in studies performed on peritoneal dialysis patients. We also analyzed the potential errors of the estimates of body composition by the formulas. RESULTS: Estimates of the average body composition provided by the anthropometric formulas agreed with estimates provided by the standard methods. However, these formulas have the potential of introducing large errors when estimating body composition in individuals differing from the average subject, either because the anthropometric formulas do not account for major determinants of body composition, such as physical exercise, nutrition, and catabolic illness, or because these formulas systematically overestimate body water in subjects who are obese or experiencing volume excess. CONCLUSION: Anthropometric formulas currently in existence can provide only approximations of body composition and may be the sources of large errors in evaluating body composition in peritoneal dialysis patients. The potential errors include estimates of body water. These errors may alter the interpretation of urea kinetic studies in certain categories of peritoneal dialysis patients (e.g., obese subjects).

Adipose Tissue↗

Reduced cholesterol levels in African-American adults with sickle cell disease.

In a recent study of boys and girls with sickle cell disease (SCD) in Nigeria, a common finding with this genetic hematologic disorder was a marked reduction in total cholesterol. Epidemiologic studies have identified a relation between low serum levels of total cholesterol (< 130 mg/dL) and increased mortality from all causes. We were interested in knowing if hypocholesterolemia was present in African-American adults with SCD. We therefore compared the plasma lipid profiles of the 16 men and 20 women with SCD who received care at the University of Texas Medical Branch at Galveston between 1996 and 2001 with those of 2,415 gender-matched African Americans who were seen at the same hospital but who did not have SCD. The age-adjusted mean total cholesterol concentrations of the SCD males and females were 147 +/- 42 mg/dL and 179 +/- 36 mg/dL, compared to male and female control values of 200 +/- 75 mg/dL and 216 +/- 61 mg/dL, respectively. These differences between SCD subjects and controls were statistically significant (p < 0.001). The LDL-cholesterol levels of the men and women with SCD (68 +/- 28 mg/dl and 95 +/- 33 mg/dl, respectively) were also significantly reduced relative to the controls (121 +/- 58 mg/dl and 128 +/- 54 mg/dl, respectively, p = 0.001). The triglyceride levels of the men with SCD were much reduced relative to the male controls (102 +/- 34 mg/dL versus 194 +/- 215 mg/dL, p = 0.02), but were not different between the SCD females and their control group. The HDL-cholesterol levels of the SCD subjects and the controls were not different. These results indicate that total cholesterol and LDL-cholesterol concentrations are significantly reduced in adult men and women with SCD in the United States, and should heighten interest in the implication that low levels of cholesterol might exacerbate the medical problems inherent in this genetic disease.

Adolescent↗

Normalization of protein nitrogen appearance by various size indicators in patients on continuous peritoneal dialysis.

Protein nitrogen appearance (PNA) estimated from urea nitrogen appearance (UNA) reflects dietary protein intake and is an important index of nutrition in peritoneal dialysis (PD). Normalization of PNA by several body size indicators has resulted in discrepancies between normalized PNA (nPNA) values and other nutrition indices in PD patients with varying weight status. To test whether a particular size indicator produces nPNA values that eliminate the discrepancies, we normalized PNA values obtained at the first clearance study in 925 PD patients by weight (W), by fat-free mass (FFM) obtained from body water, by lean body mass (LBM) derived from creatinine kinetics, by desirable weight (DW), by standard weight (SW), and by adjusted edema-fee body weight (aBW). We classified patients into three groups according to W/DW: an underweight group [group I: W/DW < 0.9, n = 147 (15.9%)], a normal-weight group [group II: 0.9 < or = W/DW < 1.2, n = 506 (54.7%)], and an obese group [group III: W/DW > or = 1.2, n = 272 (29.4%)]. The UNA and PNA increased progressively from group I to group III. The W, FFM, LBM, SW, and aBW also increased progressively, and the corresponding nPNA values decreased progressively from group I to group III--all at p < 0.001. The DW did not differ significantly between the three groups. The PNA values normalized by DW were 0.91 +/- 0.21 (group I), 0.96 +/- 0.24 (group II), and 1.07 +/- 0.25 (group III), p < 0.001. Of the six size indicators tested, only DW produced values of nPNA consistent with the nutrition status of PD patients with varying weight status. Our findings indicate that DW is the proper size indicator for normalizing PNA in PD patients.

Blood Urea Nitrogen↗

Body composition evaluation in peritoneal dialysis patients using anthropometric formulas estimating body water.

In adult patients on peritoneal dialysis (PD), estimates of body water (V), fat-free mass (FFM), and body fat (BF) can be obtained by using anthropometric formulas for estimating V. Estimates of V, FFM, and BF can also be obtained by using reference (standard) methods in which V is evaluated by a standard dilution method. To test whether the estimates obtained by the various methods agree, we analyzed published studies that measured V by a standard method in adult PD patients. We then calculated V, FFM, and BF by the Watson, Hume, Sahlgrenska, Chumlea, Lee, and Chertow formulas for the "average subject" in the published studies. We compared the standard and the anthropometric estimates using the limits-of-agreement method of Bland and Altman. Our analysis included six studies involving a total of 262 patients (89 women, 173 men). The six studies measured V by a reference method and allowed calculation of anthropometric V, FFM, and BF for the average patient. We calculated these values: VStandard, 36.8 +/- 4.7 L; VSahlgrenska, 36.9 +/- 4.3 L [p = nonsignificant (NS); Bland-Altman limits of agreement: -3.1 L to 3.3 L]; FFMStandard 50.9 +/- 5.2 kg; FFMSahlgrenska, 50.6 +/- 4.3 kg (Bland-Altman limits of agreement: -5.4 kg to 4.8 kg); BFStandard, 20.3 +/- 3.0 kg; BFSahlgrenska, 20.6 +/- 2.3 kg (Bland-Altman limits of agreement: -4.8 kg to 5.4 kg). Results obtained using the Watson, Hume, Chumlea, and Lee formulas also agreed with the standard estimates. The Chertow formula produced results that systematically overestimated the standard V and FFM values and that underestimated the standard BF. The Watson, Hume, Sahlgrenska, Chumlea, and Lee anthropometric formulas used to calculate V provide estimates of body composition that approximate those obtained using standard methods in PD patients with average body composition. Anthropometric estimates may cause large systematic errors in PD patients whose body composition varies from the average, particularly obese or overhydrated patients.

Anthropometry↗

Weight status classification of patients on continuous peritoneal dialysis.

We tested the agreement between classifications of the weight status of patients on peritoneal dialysis (PD) by body mass index (BMI) and by body fat (BF) content (BF/W, where W = actual weight), when BF was computed as BF = W - V/0.73 from the Sahlgrenska, Watson, or Hume anthropometric formulas estimating body water (V) in 933 patients on PD and 7,737 outpatients without hydration disorders. We used currently accepted cut-off values for classifying subjects as underweight, normal-weight, overweight, and obese by BMI and BF/W. We obtained these values: BMI: men on PD (n = 555), 25.5 +/- 4.3; men with normal renal function [NRF (n = 5,906)], 27.7 +/- 5.1; women on PD (n = 378), 25.9 +/- 6.1; women with NRF (n = 1,831), 28.3 +/- 6.5; BFSahlgrenska/W--men on PD, 0.238 +/- 0.063; men with NRF, 0.274 +/- 0.052; women on PD, 0.342 +/- 0.89; women with NRF, 0.366 +/- 0.075. We obtained these regressions: Women on PD BMI = 12.0832 + 38.9550 (BFSahlgrenska/W) -92.9252 (BFSahlgrenska/W)2 +254.0675 (BFSahlgrenska/W)3, r2 = 0.917; Men on PD BMI = 19.4729 - 29.1310 (BFSahlgrenska/W) +213.7045 (BFSahlgrenska/W)2, r2 = 0.888. From those regressions, the BMI value corresponding to the BFSahlgrenska/W cut-off for underweight was similar to the National Institutes of Health (NIH) BMI cut-off for underweight. The BMI value corresponding to the BFSahlgrenska/W cut-off for obesity was substantially lower than the NIH BMI cut-off for obesity. The kappa ratios of the classifications of weight status by BMI and BFSahlgrenska/W varied between 0.142 and 0.304 (poor agreement), with more than 50% of the subjects classified in a more obese weight category by BFSahlgrenska/W than by BMI. Classification of the subjects by BMI and by BFSahlgrenska/W in quintiles or quartiles led to much higher kappa ratios, particularly in women. The results were similar in subjects with NRF and with the use of the Watson and Hume formulas to estimate BF. The use of arbitrary cut-off values of BMI or anthropometric BF/W to classify PD patients or patients without edematous states as underweight, normal-weight, overweight, or obese leads to substantial disagreement between the two classifications. Classification of weight status by BMI or BF/W in quintiles or quartiles improves substantially the agreement between the two classifications and should be preferred.

Adipose Tissue↗