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Biomedical subjects

L Newell-Morris

Publications and source records attributed to L Newell-Morris.

At least 19 recordsLinked to original sources
PubMed2001

Standard definitions of overweight and central adiposity for determining diabetes risk in Japanese Americans.

BACKGROUND: Despite having lower average body mass indexes (BMIs) than do whites, Asians are at high risk of type 2 diabetes, possibly because of their greater central adiposity. The criteria for identifying individuals at risk of obesity-related conditions are usually not population specific. OBJECTIVE: Our goal was to determine whether the National Heart, Lung, and Blood Institute (NHLBI) overweight and obesity guidelines are useful for identifying diabetes risk in Japanese Americans. DESIGN: This was a prospective, cohort study of 466 nondiabetic Japanese Americans [age: 52.2 +/- 0.6 y; BMI (in kg/m(2)): 24.1 +/- 0.2; +/- SEM]. Diabetes status at a 5-y follow-up visit was assessed with an oral-glucose-tolerance test. RESULTS: Among 240 subjects aged < or = 55 y, incident diabetes was strongly associated with overweight (BMI > or = 25) at baseline [relative risk (RR): 22.4; 95% CI: 2.7, 183; adjusted for age, sex, smoking, and family history] and weight gain of > 10 kg since the age of 20 y (adjusted RR: 4.5; 95% CI: 1.4, 14.5). NHLBI definitions of central obesity (waist circumference > or = 88 cm for women and > or = 102 cm for men) were unsuitable for this population because only 15 of 240 subjects met these criteria. A waist circumference greater than or equal to the third tertile was associated with diabetes (adjusted RR: 5.4; 95% CI: 1.7, 17.0). Among 226 subjects aged >55 y, incident diabetes was not associated with BMI, weight gain, or waist circumference. CONCLUSIONS: NHLBI definitions are useful for identifying overweight Japanese Americans aged < 55 y who are at high risk of diabetes. Although central adiposity is an important risk factor, the guidelines for waist circumference are insensitive predictors of diabetes risk in this population.

Adipose Tissue↗
PubMed2000

Visceral adiposity and risk of type 2 diabetes: a prospective study among Japanese Americans.

OBJECTIVE: We conducted a prospective study among Japanese Americans of diabetes incidence in relation to visceral and regional adiposity, fasting insulin and C-peptide, and a measure of insulin secretion, because little prospective data exist on these associations. RESEARCH DESIGN AND METHODS: Baseline variables included plasma glucose, C-peptide, and insulin measured after an overnight fast and 30 and 120 min after a 75-g oral glucose tolerance test; abdominal, thoracic, and thigh fat areas by computed tomography (CT); BMI (kg/m2); and insulin secretion (incremental insulin response [IIR]). RESULTS: Study subjects included 290 second-generation (nisei) and 230 third-generation (sansei) Japanese Americans without diabetes, of whom 65 and 13, respectively, developed diabetes. Among nisei, significant predictors of diabetes risk for a 1 SD increase in continuous variables included intra-abdominal fat area (IAFA) (odds ratio, 95% CI) (1.6, 1.1-2.3), fasting plasma C-peptide (1.4, 1.1-1.8), and the IIR (0.5, 0.3-0.9) after adjusting for age, sex, impaired glucose tolerance, family diabetes history, and CT-measured fat areas other than intra-abdominal. Intra-abdominal fat area remained a significant predictor of diabetes incidence even after adjustment for BMI, total body fat area, and subcutaneous fat area, although no measure of regional or total adiposity was related to development of diabetes. Among sansei, all adiposity measures were related to diabetes incidence, but, in adjusted models, only IAFA remained significantly associated with higher risk (2.7, 1.4-5.4, BMI-adjusted). CONCLUSIONS: Greater visceral adiposity precedes the development of type 2 diabetes in Japanese Americans and demonstrates an effect independent of fasting insulin, insulin secretion, glycemia, total and regional adiposity, and family history of diabetes.

Adipose Tissue↗
PubMed1999

Bone physiology during pregnancy and lactation in young macaques.

We used a nonhuman primate model (Macaca nemestrina) of adolescent human pregnancy to characterize bone remodeling at midpregnancy and at weaning and the associated changes in bone mass. In this longitudinal study, 125 nulliparous females were followed through pregnancy, 6 months of lactation, and 3 months postweaning; 13 nonpregnant females served as controls. Between early pregnancy and midpregnancy, the whole body bone mineral increased. There was no significant change between midpregnancy and parturition. Between parturition and 3 months lactation, the animals lost 3.0% of their bone mineral (p < 0.01), which was regained by 3 months after weaning. The vertebral bone mineral apparent density decreased during pregnancy and 6 months of lactation, followed by an increase during the 3 months after weaning. Calcium, phosphate, 25-hydroxyvitamin D, and osteocalcin increased significantly from midpregnancy to weaning whereas 1,25-dihydroxyvitamin D values showed significant decreases. Histomorphometric measurements from bone biopsies showed significant increases in most parameters of bone formation between pregnancy and weaning. These results are consistent with the hypothesis that at midpregnancy bone formation is decreased and cancellous bone resorption may have increased. During lactation, losses occur in both cortical and cancellous bone, partially depleting the maternal reservoir of calcium, but a subsequent increase in bone formation enables restoration of bone mineral after weaning to values similar to those in the control group.

Adolescent↗
PubMed1999

Visceral adiposity and incident coronary heart disease in Japanese-American men. The 10-year follow-up results of the Seattle Japanese-American Community Diabetes Study.

OBJECTIVE: To identify risk factors for incident coronary heart disease (CHD). RESEARCH DESIGN AND METHODS: A total of 175 Japanese-American men without CHD were followed for up to 10 years. Baseline variables were blood pressure, weight, BMI, fat areas by computed tomography, skinfold thicknesses, abdominal circumference, plasma insulin, C-peptide, cholesterol, LDL cholesterol, HDL cholesterol, HDL2 cholesterol, and HDL3 cholesterol, triglycerides, apoproteins A1 and B, and diagnosis of diabetes and hypertension. CHD was diagnosed by electrocardiogram and clinical events. Logistic regression was used to estimate odds ratio. RESULTS: There were 50 incident cases of CHD. Using univariate logistic regression analysis, significant risk factors were intra-abdominal fat (P = 0.0090), fasting glucose (P = 0.0002), 2-h glucose (P = 0.0008), fasting HDL cholesterol (P = 0.0086), fasting HDL2 cholesterol (P = 0.030), fasting HDL3 cholesterol (P = 0.018), fasting triglycerides (P = 0.013), systolic (P = 0.0007) and diastolic blood pressure (P = 0.0002), and presence of diabetes (P = 0.0023). Multiple logistic regression models adjusted for BMI and age showed that intra-abdominal fat accounted for the effects of HDL cholesterol or triglycerides. In a multiple logistic regression model that included intra-abdominal fat, all systolic blood pressure and fasting glucose were significant. Substituting diastolic blood pressure for systolic blood pressure and 2-h glucose or diabetes status for fasting glucose produced similar results. CONCLUSIONS: Visceral adiposity, blood pressure, and plasma glucose are important independent risk factors for incident CHD in this population of diabetic and nondiabetic Japanese-American men.

Adipose Tissue↗
PubMed1998

Reduced amylin release is a characteristic of impaired glucose tolerance and type 2 diabetes in Japanese Americans.

Islet amyloid is a characteristic feature of type 2 diabetes. Its major component is the normal beta-cell secretory product amylin, or islet amyloid polypeptide (IAPP). To determine whether increased or disproportionate release of amylin may explain the propensity for amyloid deposition in type 2 diabetes, we measured plasma amylin-like immunoreactivity (ALI) and immunoreactive insulin (IRI) release in response to an oral glucose load in 94 Japanese-American subjects with normal glucose tolerance (NGT; n=56), impaired glucose tolerance (IGT; n=10), and type 2 diabetes (n=28) as defined by World Health Organization criteria. The incremental increase in ALI, IRI, and glucose (G) at 30 min after oral glucose ingestion was used to calculate deltaALI/deltaG and deltaIRI/deltaG as measures of beta-cell function. Overall glucose metabolism was assessed as the incremental glucose area (glucose AUC) during the 2 h of the oral glucose tolerance test. As expected, plasma glucose concentrations at both fasting (NGT, 5.0+/-0.4; IGT, 5.5+/-0.1; type 2 diabetes, 6.2+/-0.3 mmol/l; P < 0.0001) and 2 h (NGT, 6.7+/-0.1; IGT, 9.4+/-0.3; type 2 diabetes, 13.2 +/-0.5 mmol/l; P < 0.0001) were elevated in individuals with IGT and type 2 diabetes. In response to glucose ingestion, plasma IRI and ALI increased in all subjects, but these increments were lower in individuals with reduced glucose tolerance, as reflected in the deltaIRI/deltaG (NGT, 119+/-10.3; IGT, 60.7+/-7.1; type 2 diabetes, 49.7 +/-5.4 pmol/l; P < 0.0001) and deltaALI/deltaG (NGT, 2.6+/-0.2; IGT, 1.8+/-0.3; type 2 diabetes, 1.2+/-0.1 pmol/l; P < 0.0001). Moreover, these reductions in the 30-min incremental ALI and IRI responses were proportionate such that the molar ratio of ALI to IRI was not different among the three groups (NGT, 2.6+/-0.2; IGT, 2.9 +/-0.3; type 2 diabetes, 2.9+/-0.3%; NS). Further, the relationship between beta-cell function, measured as either deltaIRI/deltaG or deltaALI/deltaG, and glucose metabolism, assessed as glucose AUC, was nonlinear and inverse in nature, with r2 values of 0.38 (P < 0.0001) and 0.33 (P < 0.0001), respectively. We conclude that the reduced beta-cell function of IGT and type 2 diabetes includes proportionate reductions in both IRI and ALI release. Thus, it is unlikely that the development of islet amyloid in type 2 diabetes is the result of increased release of ALI.

Amyloid↗
PubMed1997

Evaluation of vertebral volumetric vs. areal bone mineral density during growth.

Bone mineral "density" (BMD) measured by dual-energy X-ray absorptiometry (DEXA) does not represent the volumetric density (grams per cubic centimeter), but rather the areal density (grams per square centimeter). This distinction is important during growth. The purpose of this study was to measure vertebral dimensions in cadavers of young pigtail macaques (Macaca nemestrina), and to derive equations to predict the volumetric bone density from noninvasive measurements. We measured the areal bone density by DEXA, vertebral volume by underwater weighing, mineral content by ashing, dimensions of lumbar vertebrae by calipers, and dimensions of vertebrae by radiography. Somatometric measurements of the female lumbar vertebral bodies showed that the shape changed during growth. The bone mineral content from the densitometer correlated significantly with the ash weight (r = 0.99, error 8.7%). The correlation coefficient between the volumetric bone mineral density and areal BMD measurement was significant (r = 0.68, p < 0.0001) with a 9.5% error; this improved significantly to 0.82 (7.2% error) when the BMD was divided by the vertebral depth from the radiograph. A real BMD showed a strong correlation with age (r = 0.82, p < 0.0001), with an average increase of 7.4%/year. In contrast, volumetric mineral density showed a weak relationship with age (r = 0.43, p < 0.01), for an average increase of 1.5%/year. When studying bone mineral density during growth, the differences between volumetric and areal bone mineral density should be taken into consideration.

Absorptiometry, Photon↗
PubMed1996

Low insulin secretion and high fasting insulin and C-peptide levels predict increased visceral adiposity. 5-year follow-up among initially nondiabetic Japanese-American men.

Insulin resistance and hyperinsulinemia occur more frequently in subjects with greater visceral adiposity, but it is not known whether these metabolic abnormalities precede or follow visceral fat accumulation. We prospectively studied the development of visceral adiposity in relation to fasting and stimulated insulin and C-peptide levels. We followed 137 nondiabetic, second-generation Japanese-American men for changes in visceral adiposity over 5 years. Intra-abdominal fat (IAF) area (square centimeters) was measured at the umbilicus by computed tomography at baseline and after 5 years. Plasma insulin and C-peptide levels were measured after an overnight fast and during an oral glucose tolerance test. Beta-cell function was measured by the insulin secretion ratio (30-0 min plasma insulin difference)/(30-0 min plasma glucose difference). After adjustment for baseline IAF in multiple linear regression models, baseline fasting insulin (coefficient = 0.241, P = 0.048) and C-peptide (coefficient = 38.538, P < 0.001) levels were positively correlated, while the baseline insulin secretion ratio was negatively correlated with IAF change (coefficient = -0.099, P = 0.027). With IAF difference coded as a dichotomous variable (> 0 cm2 vs. < or = 0 cm2), the highest versus lowest tertile of baseline fasting insulin (odds ratio [OR] = 3.0, 95% CI 1.0-9.7) and fasting C-peptide (OR = 8.1, 95% CI 2.4-26.8) levels and the lowest versus highest tertile of the insulin secretion ratio (OR = 3.3, 95% CI 1.0-10.0) were associated with higher odds of IAF gain. Greater insulin resistance and reduced insulin secretion precede visceral fat accumulation in nondiabetic Japanese-American men.

Abdomen↗
PubMed1996

Visceral adiposity, fasting plasma insulin, and lipid and lipoprotein levels in Japanese Americans.

OBJECTIVE: To examine the associations among visceral and subcutaneous adiposity, body-mass-index (BMI), fasting plasma insulin, lipid, and lipoprotein levels. DESIGN: Cross-sectional observational study. SUBJECTS: Non-diabetic second- (Nisei, n = 290) and third-generation (Sansei, n = 229) Japanese Americans. MEASUREMENTS: Intra-abdominal (IAF) and subcutaneous abdominal fat (SAF) area were measured using computed tomography. Fasting plasma insulin, lipid, and lipoprotein levels were measured using standard methods. RESULTS: Higher fasting insulin was significantly related to greater mean IAF and SAF area, plasma triglycerides, total HDL and HDL2 cholesterol in men and women of both generations. In a multiple linear regression analysis model among Nisei adjusted for gender, age, SAF, antihypertensive medication use, smoking, alcohol use, and exercise energy expenditure, IAF area and fasting insulin level were independently correlated with plasma triglycerides (IAF r = 0.22, fasting insulin r = 0.23), total HDL (IAF r = -0.29, fasting insulin r = -0.28), HDL2 (IAF r = -0.30, fasting insulin r = -0.27), and HDL3 cholesterol (IAF r = -0.19, fasting insulin r = -0.19). Among Sansei, similar associations were seen, except that fasting insulin was unrelated to total HDL or HDL3 cholesterol. These effects differed by gender in several instances. CONCLUSIONS: Both visceral adiposity and fasting insulin level are significantly and independently related to adverse levels of lipids and lipoproteins in both generations of nondiabetic Japanese Americans. The association between adverse lipid profile and visceral obesity is not mediated solely through detrimental effects of intra-abdominal fat deposition on fasting insulin level.

Adipose Tissue↗
PubMed1996

Hypertension in Japanese Americans: the Seattle Japanese-American Community Diabetes Study.

AMONG SEATTLE'S JAPANESE AMERICANS, hypertension is associated with older age, male gender (in the younger age groups), glucose intolerance (impaired glucose tolerance and diabetes), and visceral obesity (measured by computed tomography). The gender difference in prevalence of hypertension is absent in those ages 65 to 74 and in those with diabetes. In the absence of diabetes, hypertension is not associated with fasting plasma insulin levels in the older second generation, but it is in the younger third generation. The association of hypertension with plasma insulin in the third generation may be due to the association between diabetes and plasma insulin and the presence of many prediabetic individuals in this generation. About three-fourths of Japanese Americans are aware of their hypertension, slightly more than half of hypertensive Japanese Americans are being treated with anti-hypertensive medication, and of those receiving anti-hypertensive medication, less than half have their hypertension controlled. Women tend to be less aware of hypertension, to receive anti-hypertensive medication less often, and to have their hypertension less well-controlled than men.

Adult↗
PubMed1995

Visceral adiposity, fasting plasma insulin, and blood pressure in Japanese-Americans.

OBJECTIVE: To examine the associations among blood pressure, body mass index (BMI), intra-abdominal fat, and fasting plasma insulin levels among nondiabetic subjects. RESEARCH DESIGN AND METHODS: Second- (Nisei, n = 290) and third- (Sansei, n = 230) generation Japanese-American subjects without non-insulin-dependent diabetes mellitus (NIDDM) were selected from a community-based study of NIDDM incidence and complications. A cross-sectional comparison of measures obtained at the baseline visit was performed. Intra-abdominal fat (IAF) area was assessed using computed tomography. Associations among blood pressure, fasting insulin, and adiposity measures were assessed by comparison of mean values and multiple linear regression analysis. RESULTS: Hypertensive men and women had significantly higher mean IAF areas. Fasting insulin levels were somewhat higher in hypertensive subjects, with the only significant difference occurring among Sansei men. Both systolic and diastolic blood pressure correlated more strongly with IAF than BMI or skinfold thicknesses among Nisei, whereas among Sansei, IAF and BMI correlated equally well with either blood pressure. Significant positive correlations were found between fasting insulin level and blood pressure among Sansei only, even after adjustment for IAF and BMI (diastolic blood pressure-insulin coefficient = 0.24, P = 0.0043; systolic blood pressure-insulin coefficient = 0.36, P = 0.0025). CONCLUSIONS: IAF correlated more strongly with blood pressure than BMI or skinfold thicknesses among older, second-generation Japanese-Americans and was positively correlated with blood pressure among Sansei independent of fasting insulin level. Fasting insulin was significantly correlated with blood pressure independent of visceral and overall adiposity among third-generation Japanese-Americans.

Abdomen↗
PubMed1995

Earlier appearance of impaired insulin secretion than of visceral adiposity in the pathogenesis of NIDDM. 5-Year follow-up of initially nondiabetic Japanese-American men.

OBJECTIVE--To identify risk factors for development of non-insulin-dependent diabetes mellitus (NIDDM) during a 5-year longitudinal follow-up of second-generation Japanese-American (Nisei) men. RESEARCH DESIGN AND METHODS--For 5 years, 137 initially nondiabetic Nisei men were followed with 75-g oral glucose tolerance tests at the initial visit and at 2.5- and 5-year follow-up visits. Body fat distribution was assessed by computed tomography (CT) and body mass index (BMI) calculated at each visit. Fasting insulin and C-peptide, the increment of insulin and C-peptide at 30 min after the oral glucose load, intra-abdominal and total subcutaneous fat by CT, and BMI were compared between those who remained nondiabetic (non-DM) and those who had developed NIDDM at 2.5 years (DM-A) and 5 years (DM-B). RESULTS--At baseline, the DM-A group had significantly increased intra-abdominal fat, elevated fasting plasma C-peptide, and lower C-peptide response at 30 min after oral glucose. At the 2.5-year follow-up, this group had markedly increased fasting plasma insulin and decreased 30-min insulin and C-peptide response to oral glucose. The DM-B group also had significantly lower insulin response at 30 min after oral glucose at baseline but no significant difference in intra-abdominal fat or fasting plasma insulin and C-peptide levels. When this group developed NIDDM by 5-year follow-up, however, an increase of intra-abdominal fat was found superimposed on the pre-existing lower insulin response. Fasting plasma insulin and C-peptide remained low. CONCLUSION--In DM-A, lower 30-min insulin response to oral glucose (an indicator of beta-cell lesion) and increased intra-abdominal fat and fasting C-peptide (indicators of insulin resistance) were the risk factors related to the development of NIDDM. DM-B subjects had a lower 30-min insulin response to oral glucose at baseline and increased intra-abdominal fat at 5-years, when they were found to have NIDDM. Thus, both insulin resistance and impaired beta-cell function contribute to the development of NIDDM in Japanese-Americans, and impaired beta-cell function may be present earlier than visceral adiposity in some who subsequently develop NIDDM.

Adipose Tissue↗
PubMed1993

Dermatoglyphic asymmetry in fetal alcohol syndrome.

The hypothesis was tested that prenatal alcohol exposure disrupts developmental homeostasis, as reflected in increased dermatoglyphic fluctuating asymmetry. Twenty-two patients with fetal alcohol syndrome (FAS) and 9 with fetal alcohol effect (FAE) were matched for sex with 31 controls. On each patient, the right a-b dermal ridge count was subtracted from the left to obtain the asymmetry value. Group differences were tested by analysis of variance (ANOVA), and paired two-tailed t tests. Mean asymmetry increased from control (1.94) through FAE (2.78) to the FAS (4.00) group. Group differences were significant by ANOVA (p = 0.0066); only the FAS and control group differed by t test (p = 0.0025). The results support the hypothesis of increased decanalization of prenatal development in the presence of alcohol.

Adolescent↗
PubMed1991

Relationship of absence or presence of a family history of diabetes to body weight and body fat distribution in type 2 diabetes.

In a study sample of second generation Japanese American men (age range 45-74 years), family history of diabetes in a sibling or parent was present in 69 men (24 of 79 normal men and 45 of 78 type 2 diabetic men, P less than 0.001). Both general adiposity and body fat distribution have been associated with type 2 diabetes. Our hypothesis was that the association of both overall adiposity and of larger specific regional fat deposits with type 2 diabetes would differ depending upon family history. The relationships between diabetes and differences in general adiposity (whether current or maximum lifetime body mass index or BMI, sum of skinfolds, or sum of computed tomography or CT fat areas) and between diabetes and body fat distribution (measured as abdominal and thigh circumferences, cross-sectional body fat areas by CT of thorax, abdomen, and thigh, and skinfold thicknesses of triceps, biceps, forearm, chest, subscapula, abdomen, and thigh) were more apparent in those men without a family history of diabetes than in those with a family history. In men without a family history, diabetic men had significantly higher values for several variables which assessed overall adiposity: current BMI (P less than 0.001), maximum lifetime BMI (P less than 0.001), sum of skinfolds (P less than 0.006), and sum of CT fat areas (P less than 0.015). In addition several measurements of upper truncal adiposity were significantly increased in diabetic men: abdominal circumference (P less than 0.004), thoracic (P less than 0.015) and abdominal (P less than 0.03) subcutaneous CT fat areas, intra-abdominal CT fat areas (P less than 0.001), and chest (P less than 0.03) and subscapular (P less than 0.0002) skinfold thicknesses. The results pertaining to those without a family history appear to be due to increased adiposity and associated larger specific regional fat depots leading to diabetes and lesser adiposity and smaller amounts of fat in the same regional depots protecting against diabetes.

Adipose Tissue↗
PubMed1991

Postnatal growth and skeletal maturation of experimental preterm macaques (Macaca nemestrina).

The growth and skeletal maturation of nine preterm female pigtailed macaques (Macaca nemestrina) obtained by C-section at less than or equal to 155 postconceptional days were followed through six months of age. At C-section they were of normal size and maturation for gestational age. Compared with 50 normal females born at term (mean = 173 +/- 6.4 postconceptional days), preterm infants were also of normal size at term, but delayed in skeletal maturation, requiring about one month to achieve the standard.

Animals↗
PubMed1988

Development of dermal ridges in the volar skin of fetal pigtailed macaques (Macaca nemestrina).

Development of the dermal ridges in volar skin was investigated in 28 pigtailed macaque (Macaca nemestrina) fetuses of known gestational age, ranging from 51 days postconception to newborn. Histology, scanning electron microscopy, and staining of the abraded dermal surface were used in the study. Morphological features of the dermal-epidermal system and their changes with advancing age are described. Chronology was established for stages in the development of the volar skin, i.e., the differentiation of the primary and secondary epidermal ridges (PER and SER) at the undersurface of the epidermis corresponding to the formation of primary and secondary dermal ridges (PDR and SDR) and the development of the dermal papillae. PDRs were first seen at 55 gestational days and SDRs at 93 days. Differentiation of sweat ducts occurred over the period between 60 and 119 gestational days. A regional sequence of differentiation starting with the digital apices of the hand and ending in the calcar area and the phalanges of the foot was documented. Generally, morphogenesis in the macaque was accelerated relative to that in the human fetus by approximately 3 weeks.

Animals↗