Prediction of fat-free mass using bioelectrical impedance analysis in young adults from five populations of African origin.

BACKGROUND/OBJECTIVES: Bioelectrical impedance analysis (BIA) is used in population and clinical studies as a technique for estimating body composition. Because of significant under-representation in existing literature, we sought to develop and validate predictive equation(s) for BIA for studies in populations of African origin. SUBJECTS/METHODS: Among five cohorts of the Modeling the Epidemiologic Transition Study, height, weight, waist circumference and body composition, using isotope dilution, were measured in 362 adults, ages 25-45 with mean body mass indexes ranging from 24 to 32. BIA measures of resistance and reactance were measured using tetrapolar placement of electrodes and the same model of analyzer across sites (BIA 101Q, RJL Systems). Multiple linear regression analysis was used to develop equations for predicting fat-free mass (FFM), as measured by isotope dilution; covariates included sex, age, waist, reactance and height(2)/resistance, along with dummy variables for each site. Developed equations were then tested in a validation sample; FFM predicted by previously published equations were tested in the total sample. RESULTS: A site-combined equation and site-specific equations were developed. The mean differences between FFM (reference) and FFM predicted by the study-derived equations were between 0.4 and 0.6 kg (that is, 1% difference between the actual and predicted FFM), and the measured and predicted values were highly correlated. The site-combined equation performed slightly better than the site-specific equations and the previously published equations. CONCLUSIONS: Relatively small differences exist between BIA equations to estimate FFM, whether study-derived or published equations, although the site-combined equation performed slightly better than others. The study-derived equations provide an important tool for research in these understudied populations.

The effect of antenatal factors and postnatal growth on serum adiponectin levels in children.

Low levels of serum adiponectin (i.e. hypoadiponectinaemia) are a marker of cardiometabolic risk in overweight children. It is not clear whether early-life factors may play a role in the development of hypoadiponectinaemia. We investigated whether antenatal factors and postnatal growth are associated with childhood adiponectin levels. This was an observational study in a birth cohort (Vulnerable Windows Cohort Study). Anthropometry was measured at birth, at 6 weeks, every 3 months up to 2 years and then every 6 months. Fasting glucose, insulin, lipids and adiponectin were measured at a mean age 11.5 years. Data on 323 children were analysed with age- and sex-adjusted multivariate analyses. The sizes of mother, placenta, fetus and newborn were not significantly associated with adiponectin levels. Current weight, body mass index (BMI), fat mass, waist circumference, glucose, insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)], triglycerides and systolic blood pressure were inversely related to adiponectin (P < 0.05). Faster growth in BMI during late infancy and childhood was associated with lower adiponectin levels (P < 0.05). After adjusting for current waist circumference, faster growth in BMI during early infancy was positively associated with adiponectin (P < 0.01). Faster growth in BMI during childhood was inversely associated (P < 0.001). These associations were similar after adjusting for HOMA-IR. We concluded that antenatal factors are not determinants of childhood adiponectin levels. Faster growth in BMI during infancy is associated with higher levels, whereas faster rates during childhood are associated with hypoadiponectinaemia. Hypoadiponectinaemia is a marker of a more adverse cardiometabolic profile in Afro-Caribbean children.

The effect of feto-maternal size and childhood growth on left ventricular mass and arterial stiffness in Afro-Caribbean children.

We hypothesized that maternal size, fetal size and childhood growth are associated with childhood blood pressure, left ventricular mass (LVM) and arterial stiffness. The Vulnerable Windows Cohort is a longitudinal study of 569 mothers and their offspring. Anthropometry was measured on each child at birth, at 6 weeks, once in 3 months upto 2 years and then every 6 months. Blood pressure and body composition were assessed in 185 children (age 11.5 years) and echocardiography performed. LVM was not associated with maternal size after adjustment for child's weight. LVM was significantly associated with faster growth in childhood and with current weight, fat mass and lean mass. Systolic blood pressure was not related to maternal, fetal or newborn anthropometry, but was positively associated with infant and childhood growth, as well as current body size and fat mass. The pulse pressure/stroke volume ratio (an index of arterial stiffness) was inversely associated with maternal size, placental volume at 20 weeks, fetal size at 35 weeks and childhood growth even after adjustment for current weight. In conclusion, LVM in childhood is positively associated with maternal height, child's current size and rate of growth. Arterial stiffness is inversely related to maternal, fetal and placental size as well as growth throughout childhood.

Predictors of physical activity energy expenditure in Afro-Caribbean children.

BACKGROUND/OBJECTIVES: We hypothesized that maternal size during pregnancy and birth size are determinants of childhood physical activity energy expenditure (PAEE). Also, childhood PAEE is inversely related to adiposity and levels of cardiovascular risk factors. SUBJECTS/METHODS: The Vulnerable Windows Cohort Study is a longitudinal observational study of 569 Afro-Jamaican mothers recruited from the first trimester and their offspring. Anthropometry, bioelectrical impedance, PAEE (using the Actical monitor) and cardiovascular risk factors (blood pressure, fasting glucose, insulin and lipids) were measured in 124 boys and 160 girls at a mean age of 13.2 years. RESULTS: Boys had more fat-free mass (FFM) and expended more energy than girls (12.3±3.3 vs 9.6±2.8 kcal/kg/day; P<0.001). Maternal weight was associated with child's PAEE (r=0.29; P<0.001). PAEE was not significantly associated with birth weight. Maternal weight, after adjusting for child's age and sex, was positively associated with the child's FFM, fat mass and %fat (P-values 0.01). Age- and sex-adjusted PAEE was positively associated with FFM, fat mass and % fat (P-values <0.001), but not after adjusting for current weight. Age- and sex-adjusted PAEE was positively associated with triglycerides, insulin and systolic blood pressure (P-values <0.05), but not after adjusting for weight and height. PAEE was associated with fasting glucose after controlling for age, sex, weight and height (r=-0.12; P=0.02). CONCLUSIONS: Maternal size, but not birth weight, is a determinant of childhood PAEE. PAEE is not strongly associated with childhood body composition, but is inversely related to fasting glucose concentration.

Progression from prehypertension to hypertension in a Jamaican cohort: incident hypertension and its predictors.

OBJECTIVES: To estimate the incidence of hypertension in people with and without prehypertension and determine the factors that predict progression to hypertension. METHODS: Data from a cohort of 25-74-year-old residents of Spanish Town, Jamaica, were analysed. All participants completed a structured questionnaire and had blood pressure (BP), anthropometric measurements and venous blood sampling performed by trained personnel. Blood Pressure was classified using the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC-7) criteria. RESULTS: 708 persons who had the required data and were not hypertensive at baseline were included in this analysis. Mean follow-up time was 4.1 years; 28.7% of prehypertensive participants developed hypertension compared to 6.2% of normotensive participants. The unadjusted incidence rate ratio (IRR [95% CI]) for progression among prehypertensive compared to normotensive participants was 4.62 [2.96, 7.43]. Among males, the rate of progression to hypertension was significantly higher for those 45-64 years old and those who were current smokers. Among females, progression was higher for age groups 25-44 years, 45-64 years, those who were overweight (BMI > or =25), obese (BMI > or =30) and current smokers. In multivariate models, prehypertension, female gender overweight status and older age remained significantly associated with progression to hypertension among the combined prehypertensive and normotensive groups. IRR [95% CI] were: prehypertension, 3.45 [2.18-5.45]; female gender 1.81 [1.12, 2.94]; overweight, 1.87 [1.15, 2.94]; age 45-64 years, 1.73 [1.08, 2.76]; age > 65 years 2.39 [1.31, 4.34]. CONCLUSIONS: Prehypertension is associated with a three-fold increase in the incidence of hypertension. Higher BMI, age and female gender also independently predict the development of hypertension.

Prevalence of the metabolic syndrome in Jamaican adults and its relationship to income and education levels.

OBJECTIVE: To estimate the prevalence of the metabolic syndrome in Jamaican adults and to evaluate its association with socio-economic status (SES). METHODS: A cross-sectional analysis was performed using data from a cohort study of persons, 25-74 years old, living in St Catherine, Jamaica, and who were evaluated between 1993 and 2001. Participants completed an interviewer administered questionnaire and had blood pressure and anthropometric measurements performed by trained observers. Venous blood was collected for measurement of fasting glucose and lipids. The metabolic syndrome was defined using the International Diabetes Federation (IDF) and American Heart Association/National Heart Lung and Blood Institute (AHA/NHLBI) criteria. Income and education were used as markers of SES. RESULTS: Data from 1870 participants (717 males 1153 females) were analysed. Prevalence of the metabolic syndrome was 21.1% (95% CI 19.2, 22.9%) using IDF criteria and 18.4% (95% CI 16.6, 20.2%) using the AHA/NHLBI criteria. Prevalence was higher among females (27.6% [IDF], 23.0% [AHA]) compared to males (10.6% [IDF], 11.0% [AHA]). The prevalence of the metabolic syndrome increased with age. Compared to males with primary/lower education, those with secondary and tertiary education had higher odds of having the metabolic syndrome after adjusting for age; odds ratio 3.12 (1.54, 6.34) and 2.61 (1.33, 5.11) respectively. High income was also associated with increased odds of having the metabolic syndrome among males, OR = 6.0 (2.22, 16.19) adjusting for age-group. There were no significant associations among women. CONCLUSION: The metabolic syndrome is common in Jamaica. Clinicians should look for this syndrome in their patients and take steps to treat the abnormalities identified.

A comparative study of the quality and availability of health information used to facilitate cost burden analysis of diabetes and hypertension in the Caribbean.

OBJECTIVE: Non-communicable Diseases (NCDs) are leading threats to health and well-being in the Caribbean. A study was undertaken in the latter part of 2005 to compute the economic burden of diabetes mellitus and hypertension within the Caribbean Community and Common Market (CARICOM). This report critiques the quality and availability of health information which can be used to facilitate cost burden analysis of diabetes mellitus and hypertension. METHODS: A form was developed and disseminated to obtain epidemiological and health service utilization data. Subsequent visits were made to seven CARICOM member countries to collect the data. RESULTS: The results revealed (i) a number of deficiencies in the reliability and validity of the data received, in particular, those needed to facilitate the analysis of cost-specific complications such as ischaemic heart disease, cerebrovascular disease, chronic renal failure, hypertensive and diabetic retinopathy and peripheral circulatory complications; (ii) data management systems in hospitals were not linked to facilitate generation of cost-effectiveness estimates and other information required to compare options for health investment; (iii) despite repeated attempts by regional governments to develop/strengthen Health Information Systems within the Caribbean, sustainability has been significantly hampered by human, material and financial resource constraints and ongoing monitoring and evaluation is generally poor. CONCLUSION: There are deficiencies in the quality and availability of health information to facilitate cost burden analysis of hypertension and diabetes mellitus in the Caribbean Strong commitment from CARICOM governments will be necessary to address these concerns if economic evaluations are to be undertaken more frequently as part of the effort to reduce the morbidity and mortality from these diseases.

Activity, adiposity and weight change in Jamaican adults / Actividad, adiposidad y cambio de peso en los adultos jamaicanos

OBJECTIVE: Populations in developing countries are particularly vulnerable to the development of obesity in the period of rapid transition to a more modernized lifestyle. We sought to determine the relationship between activity energy expenditure (AEE), adiposity and weight change in an adult population undergoing rapid socio-economic transition. METHODS: Total daily energy expenditure (TDEE) was measured using the doubly labelled water method, resting energy expenditure (REE) using indirect calorimetry and AEE calculated as the difference between TDEE and REE, in adults from a working class community in Spanish Town, Jamaica. During six years of follow-up, weight was measured between one and four times. Mixed effects regression modelling was used to test for association between components of the energy budget and weight change. RESULTS: Men (n = 17) weighed more but women (n = 18), had significantly more body fat, 38.5% vs 24.5%, respectively (p < 0.01). Men had higher levels of EE, particularly AEE after adjustment for body weight, 66.3 versus 46.4 kJ/kg.d for men and women, respectively (p < 0.001). At baseline, adjusted AEE was inversely associated with body fat in men and women, r = -0.46 and r = -0.48, respectively (p < 0.05). Mean rate of weight change was + 1.1 and + 1.2 kg/year for men and women, respectively. No component of EE, ie TDEE, REE or AEE, significantly predicted weight change in this small sample. CONCLUSIONS: These results suggest an important role for AEE in maintaining low levels of adiposity. The lack of association between EE and weight change, however, suggests populations in transition are at risk of obesity from environmental factors (eg dietary) other than simply declining physical activity levels.

OBJETIVO: Las poblaciones en los países en vía de desarrollo son particularmente vulnerables al desarrollo de la obesidad en el período de rápida transición a un estilo de vida más moderno. Buscamos determinar la relación entre el gasto energético por actividad (GEA), la adiposidad y el cambio de peso en una población adulta en proceso de rápida transición socio-económica. MÉTODOS: El gasto energético total diario (GETD) fue medido usando el método del agua doblemente marcada, gasto energético en reposo (GER) usando calorimetría indirecta y el GEA calculado como la diferencia entre GETD y GER, en adultos de una comunidad de clase obrera en Spanish Town, Jamaica. Durante seis años de seguimiento, el peso fue medido entre una y cuatro veces. Un modelo de regresión de efectos mixtos fue usado para probar la asociaciF3n entre los componentes del presupuesto de la energEDa y el cambio de peso. RESULTADOS: Los hombres (n = 17) pesaron más pero las mujeres (n = 18) teníEDan significativamente más grasa corporal, 38.5% frente a 24.5%, respectivamente (p < 0.01). Los hombres tenían niveles más altos de GE, particularmente GEA después del ajuste por peso corporal, 66.3 frente a 46.4 kJ/kg.d para los hombres y mujeres, respectivamente (p < 0.001). Al inicio, el GEA ajustado estaba inversamente asociado con la grasa del cuerpo en los hombres y mujeres, r = -0.46 y r = -0.48, respectivamente (p < 0.05). La tasa media de cambio de peso fue +1.1 y +1.2 kg/ano para los hombres y mujeres, respectivamente. Ningún componente de GE, es decir, GETD, GER o GEA, predijo significativamente el cambio de peso en esta muestra pequeña. CONCLUSIONES: Estos resultados sugieren un papel importante del GEA en cuanto a mantener niveles bajos de adiposidad. Sin embargo, la falta de asociación entre GE y cambio de peso, sugiere que las poblaciones en transición corren el riesgo de obesidad debido a factores ambientales (p.ej. dietéticos) distintos de la mera...

Activity, adiposity and weight change in Jamaican adults.

OBJECTIVE: Populations in developing countries are particularly vulnerable to the development of obesity in the period of rapid transition to a more modernized lifestyle. We sought to determine the relationship between activity energy expenditure (AEE), adiposity and weight change in an adult population undergoing rapid socio-economic transition. METHODS: Total daily energy expenditure (TDEE) was measured using the doubly labelled water method, resting energy expenditure (REE) using indirect calorimetry and AEE calculated as the difference between TDEE and REE, in adults from a working class community in Spanish Town, Jamaica. During six years of follow-up, weight was measured between one and four times. Mixed effects regression modelling was used to test for association between components of the energy budget and weight change. RESULTS: Men (n = 17) weighed more but women (n = 18), had significantly more body fat, 38.5% vs 24.5%, respectively (p < 0.01). Men had higher levels of EE, particularly AEE after adjustment for body weight, 66.3 versus 46.4 kJ/kg.d for men and women, respectively (p < 0.001). At baseline, adjusted AEE was inversely associated with body fat in men and women, r = -0.46 and r = -0.48, respectively (p < 0.05). Mean rate of weight change was + 1.1 and + 1.2 kg/year for men and women, respectively. No component of EE, ie TDEE, REE or AEE, significantly predicted weight change in this small sample. CONCLUSIONS: These results suggest an important role for AEE in maintaining low levels of adiposity. The lack of association between EE and weight change, however, suggests populations in transition are at risk of obesity from environmental factors (eg dietary) other than simply declining physical activity levels.

Skin test reactivity to aeroallergens in Jamaicans: relationship to asthma.

BACKGROUND: Asthma causes significant morbidity and mortality in the developing world. It is thus important to identify modifiable risk factors. OBJECTIVES: To undertake a cross-sectional study to determine the prevalence of skin test reactivity to aeroallergens in Jamaican children and adults and the relationship of the diagnosis of asthma to the pattern of skin test positivity. METHODS: One hundred and sixty subjects without the sickle cell gene (genotype AA), eighty adults and eighty children, were recruited. Skin testing to seven aeroallergens was undertaken (atopy being diagnosed if there were at least one positive reaction). Asthma status was determined by a questionnaire and/or medical records. RESULTS: Twenty-seven (34%) of the children and forty-one (51%) of the adults were skin test positive to at least one aeroallergen. The most common positive responses in both age groups were to Dermatophagoides farinae, Dermatophagoides pteronyssinus and cockroach mix-(German and American). All adult asthmatics with current symptoms reacted to cockroach allergen. CONCLUSIONS: Appropriate steps to reduce cockroaches and cockroach sensitization might positively impact on asthma morbidity in Jamaica.

Skin test reactivity to aeroallergens in Jamaicans: relationship to asthma / Reactividad de la prueba cutánea frente a aeroalérgenos en los jamaicanos: relación con el asma

BACKGROUND: Asthma causes significant morbidity and mortality in the developing world. It is thus important to identify modifiable risk factors. OBJECTIVES: To undertake a cross-sectional study to determine the prevalence of skin test reactivity to aeroallergens in Jamaican children and adults and the relationship of the diagnosis of asthma to the pattern of skin test positivity. METHODS: One hundred and sixty subjects without the sickle cell gene (genotype AA), eighty adults and eighty children, were recruited. Skin testing to seven aeroallergens was undertaken (atopy being diagnosed if there were at least one positive reaction). Asthma status was determined by a questionnaire and/or medical records. RESULTS: Twenty-seven (34) of the children and forty-one (51) of the adults were skin test positive to at least one aeroallergen. The most common positive responses in both age groups were to Dermatophagoides farinae, Dermatophagoides pteronyssinus and cockroach mix-(German and American). All adult asthmatics with current symptoms reacted to cockroach allergen. CONCLUSIONS: Appropriate steps to reduce cockroaches and cockroach sensitization might positively impact on asthma morbidity in Jamaica.

ANTECíENTES: El asma causa morbilidad y mortalidad significativas en el mundo en desarrollo. Por lo tanto, es importante identificar los factores de riesgo modificables. OBJETIVOS: Llevar a cabo un estudio transversal a fin de determinar la prevalencia de la reactividad de la prueba cutánea frente a los aeroalérgenos en niños y adultos jamaicanos, y la relación del diagnóstico del asma con el patrón de positividad de la prueba cutánea. MÉTODOS: Se reclutaron ciento sesenta sujetos AA (sin genes falciformes), ochenta adultos y ochenta niños. Se llevaron a cabo pruebas cutáneas frente a siete aeroalérgenos (diagnosticándose atopia si se producía al menos una reacción positiva). El estatus asmático se determinó mediante encuestas y/o historias clínicas. RESULTADOS: Veintisiete (34%) de los niños y cuarenta y uno (51%) de los adultos, resultaron positivos en la prueba cutánea, al menos a un aeroalérgeno. Las respuestas positivas más comunes en ambos grupos de edad fueron frente a Dermatophagoides farinae, Dermatophagoides pteronyssinus, y mezcla de cucarachas (alemanas y americanas). Todos los asmáticos adultos con síntomas usuales reaccionaron al alérgeno de la cucaracha. CONCLUSIONES: Medidas apropiadas a fin de reducir las cucarachas y la sensibilización a las cucarachas podría tener un impacto positivo en la morbilidad por asma en Jamaica.

Iron deficiency anaemia in Jamaican children, aged 1-5 years, with sickle cell disease / Anemia por deficiencia de hierro en los niños jamaicanos entre 1 y 5 años de edad, que padecen la enfermedad de células falciformes

OBJECTIVE: The aim of this study was to determine, using a combination of measures, the prevalence of iron deficiency anaemia (IDA) in children under five years-of-age who have sickle cell disease (SCD) and attend the Sickle Cell Clinic (SCU) of the Tropical Medicine Research Institute. MATERIALS AND METHODS: Children with homozygous sickle cell anaemia (Hb SS) or doubly heterozygous for Hb S and Hb C (Hb SC) disease who had not received a blood transfusion within three months prior to the iron measurements, were enrolled. The diagnosis of IDA was made if transferrin saturation was less than 16with serum iron less than 10.7 micromol/l and a low mean corpuscular volume (MCV) for age. RESULTS: Twelve children (8.5), seven with Hb SS and five with Hb SC had IDA. Adjusting for genotype, children with IDA had significantly higher red blood cell (RBC) counts (4.3 x10(9)/l vs 3.0 x 10(9)/l, p < 0.001) and total iron binding capacity (TIBC) (65.6 micromol/l vs 55.2 micromol/l, p < 0.004) but significantly lower reticulocyte (retic) counts (7.8vs 12.2, p = 0.001) than children without IDA. CONCLUSION: Iron deficiency anaemia is a clinical problem which affects children with SCD in Jamaica. The higher RBC counts in the IDA group may be due to decreased haemolysis and increased red cell survival whilst the lower reticulocyte counts may be due to impaired erythropoiesis. These observations need to be extended by clinical studies to establish improved diagnostic measures for IDA in SCD. Additionally, clinical trials are needed to determine whether treatment of IDA in children with SCD reduces morbidity and is associated with clinical benefits such as improvements in neurocognitive function.

OBJETIVO: El objetivo de este estudio fue determinar – mediante una combinacion de medidas – la prevalencia de anemia por deficiencia de hierro (ADH) en ninos menores de cinco anos de edad que padecen la enfermedad de celulas falciformes (ECF), y asisten a la Clinica de Celulas Falciformes (CCF) del Instituto de Investigacion de Medicina Tropical. MATERIALES Y MÉTODOS: Se inscribieron ninos con anemia de celulas falciformes homocigoticas (Hb SS) o enfermedad doble heterocigoto por Hb S y Hb C (Hb SC), que no habian recibido transfusion de sangre por un periodo de tres meses antes de las mediciones de hierro. Se diagnosticaba ADH si la saturacion de la transferrina era menos del 16%, con hierro en suero inferior a 10.7 mol/l, y un volumen corpuscular medio (VCM) bajo para la edad.RESULTADOS: Doce ninos (8.5%), siete con Hb SS y cinco con Hb SC presentaban ADH. despues del ajuste de las diferencias en el genotipo, los ninos con ADH tuvieron conteos de globulos rojos (RBC) (4.3 x109/l vs 3.0 x 109/l, p < 0.001), y capacidad total de fijacion del hierro (TIBC) (65.6 mmol/l vs 55.2 mmol/l, p < 0.004) significativamente mas altos, pero conteos de reticulocitos (7.8% vs 12.2%, p = 0.001) significativamente mas bajos que los ninos sin ADH. CONCLUSIÓN: La anemia por deficiencia de hierro es un problema clinico que afecta a los ninos con ECF en Jamaica. El hecho de que los conteos de RBC sean mas altos en los grupos con ADH, puede deberse a una disminución de la hemólisis y un aumento de la upervivencia de glóbulos rojos, en tanto que los conteos más bajos de reticulocitos pueden deberse a problemas de eritropoyesis. Estas observaciones necesitan ser ampliadas mediante estudios clínicos para establecer las medidas de diagnóstico mejoradas para ADH en ECF. Además de ello, se requieren ensayos clínicos a fin de determinar si el tratamiento de ADH en niños con ECF reduce la morbosidad y se halla asociado con beneficios clínicos...

SNP haplotypes in the angiotensin I-converting enzyme (ACE) gene: analysis of Nigerian family data using gamete competition models.

Gamete competition models were used to explore the relationships between 13 ACE gene polymorphisms and plasma ACE concentration in a set of Nigerian families. Several markers in the 5' and 3' regions of the gene were significantly associated with ACE concentration (P < 10(-4)). Multi-locus genotypes comprising different combinations of markers from the 5' UTR and the 3' region of the gene were also analysed; in addition to G2350A, in the 3' region, two markers from the 5' UTR (A-5466C and A-240T) were found to be associated with ACE concentration. These results are consistent with reports that have suggested the presence of at least two ACE-linked QTLs, and demonstrate the utility of gamete competition models in the exploratory investigation of the relationship between a quantitative trait and multiple variants in a small genomic region.

Cold-induced elevation of forearm vascular resistance is inversely related to birth weight.

Fetal growth retardation has been linked to elevated blood pressure in adult life. This association between birth weight and blood pressure is present in childhood and is amplified with age. However, the mechanisms that underlie this association are largely unknown. We examined the relationship between birth weight and forearm vascular resistance and forearm blood flow in children aged 9-12.7 years. A total of 58 children were randomly selected from a cohort of 1610 born at the University Hospital of the West Indies in Jamaica where adequate antenatal and delivery records were available. Blood pressure, heart rate and forearm blood flow (by venous occlusion plethysmography) were measured at rest and after cold pressor and mental arithmetic tests. There was a significant inverse correlation between birth weight and the change in the vascular resistance for the cold pressor test (r=-0.47; P<0.001) and the mental arithmetic stress test (r=-0.26; P=0.05). The log ratio of vascular resistance under stress to resting decreased by 0.289 units per kg of birth weight (95% CI: 0.145-0.434; P=0.0002). Lower birth weight is associated with increased vascular responsiveness. Increased vascular resistance might be one mechanism linking fetal growth to subsequent elevated blood pressure.

Iron deficiency anaemia in Jamaican children, aged 1-5 years, with sickle cell disease.

OBJECTIVE: The aim of this study was to determine, using a combination of measures, the prevalence of iron deficiency anaemia (IDA) in children under five years-of-age who have sickle cell disease (SCD) and attend the Sickle Cell Clinic (SCU) of the Tropical Medicine Research Institute. MATERIALS AND METHODS: Children with homozygous sickle cell anaemia (Hb SS) or doubly heterozygous for Hb S and Hb C (Hb SC) disease who had not received a blood transfusion within three months prior to the iron measurements, were enrolled. The diagnosis of IDA was made if transferrin saturation was less than 16% with serum iron less than 10.7 micromol/l and a low mean corpuscular volume (MCV) for age. RESULTS: Twelve children (8.5%), seven with Hb SS and five with Hb SC had IDA. Adjusting for genotype, children with IDA had significantly higher red blood cell (RBC) counts (4.3 x10(9)/l vs 3.0 x 10(9)/l, p < 0.001) and total iron binding capacity (TIBC) (65.6 micromol/l vs 55.2 micromol/l, p < 0.004) but significantly lower reticulocyte (retic) counts (7.8 % vs 12.2%, p = 0.001) than children without IDA. CONCLUSION: Iron deficiency anaemia is a clinical problem which affects children with SCD in Jamaica. The higher RBC counts in the IDA group may be due to decreased haemolysis and increased red cell survival whilst the lower reticulocyte counts may be due to impaired erythropoiesis. These observations need to be extended by clinical studies to establish improved diagnostic measures for IDA in SCD. Additionally, clinical trials are needed to determine whether treatment of IDA in children with SCD reduces morbidity and is associated with clinical benefits such as improvements in neurocognitive function.

Energetic determinants of glucose tolerance status in Jamaican adults.

As type 2 diabetes mellitus (DM2), obesity and sedentary lifestyles are increasing in developing countries, this observational study investigated the role of physical activity on DM2 in Jamaica. Anthropometry, body composition (by bioelectrical impedance analysis) and glucose tolerance status was assessed in 722 adults in 1993 and 1997. Energy expenditure was estimated in a subset using measured resting energy expenditure in combination with self-reported activity recalls. The rates of impaired glucose tolerance (IGT) were 23.7 and 27.3%, and DM2 were 16.3 and 23.7% among men and women, respectively. After adjusting for body composition, a one-unit increase in physical activity significantly reduced the odds of having diabetes (OR = 0.05; 95% CI: 0.004, 0.66), but not IGT. Hence, decreased physical activity is a significant independent contributor to the high rates of glucose intolerance in Jamaica. Efforts must be directed at minimizing obesity and increasing physical activity in developing countries.

Features of isolated post-challenge hyperglycaemia in Jamaican adults.

Isolated post-challenge hyperglycaemia (IPH) can be defined as a two-hour plasma glucose concentration > or = 11.1 mmol/L with a fasting plasma glucose concentration < 7.0 mmol/L. The aim of this prospective study was to determine the prevalence of IPH in a cohort of Jamaican individuals, and to determine if simple clinical features may predict the presence and subsequent diagnosis of IPH. A cohort of 1694 adults aged 25-74 years without physician-diagnosed diabetes mellitus was randomly selected. An oral glucose tolerance test (OGTT) was performed. Anthropometry, blood pressure and lipid profiles were measured. The prevalence of undiagnosed diabetes mellitus by the 1999 World Health Organization criteria was 6.4%. IPH accounted for 24% of these cases and 1.4% of the entire population. Individuals with IPH were significantly older, with greater body mass index, waist-hip ratio, systolic blood pressure, fasting blood glucose, total cholesterol and LDL-cholesterol than individuals with normal glucose tolerance. Individuals with IPH were not significantly different from individuals with fasting plasma glucose levels > or = 7 mmol/L (i.e. fasting hyperglycaemia) in anthropometry or blood pressure. However, total cholesterol and LDL-C were significantly elevated in the IPH group. OGTT screening of individuals with impaired fasting glucose (i.e. 6.1-6.9 mmol/l) could reduce the IPH group by 50%. Reducing the threshold for fasting glucose to 5.6 mmol/L would correctly classify 87% of the population. We concluded that individuals with IPH have features of the metabolic syndrome, which can aid in selection for screening. OGTT screening of individuals with fasting glucose values of 5.6-6.9 mmol/l is needed to identify IPH.

Features of isolated post-challenge hyperglycaemia in Jamaican adults

Isolated post-challenge hyperglycaemia (IPH) can be defined as a two-hour plasma glucose concentration > or = 11.1 mmol/L with a fasting plasma glucose concentration < 7.0 mmol/L. The aim of this prospective study was to determine the prevalence of IPH in a cohort of Jamaican individuals, and to determine if simple clinical features may predict the presence and subsequent diagnosis of IPH. A cohort of 1694 adults aged 25-74 years without physician-diagnosed diabetes mellitus was randomly selected. An oral glucose tolerance test (OGTT) was performed. Anthropometry, blood pressure and lipid profiles were measured. The prevalence of undiagnosed diabetes mellitus by the 1999 World Health Organization criteria was 6.4. IPH accounted for 24 of these cases and 1.4 of the entire population. Individuals with IPH were significantly older, with greater body mass index, waist-hip ratio, systolic blood pressure, fasting blood glucose, total cholesterol and LDL-cholesterol than individuals with normal glucose tolerance. Individuals with IPH were not significantly different from individuals with fasting plasma glucose levels > or = 7 mmol/L (i.e. fasting hyperglycaemia) in anthropometry or blood pressure. However, total cholesterol and LDL-C were significantly elevated in the IPH group. OGTT screening of individuals with impaired fasting glucose (i.e. 6.1-6.9 mmol/l) could reduce the IPH group by 50. Reducing the threshold for fasting glucose to 5.6 mmol/L would correctly classify 87 of the population. We concluded that individuals with IPH have features of the metabolic syndrome, which can aid in selection for screening. OGTT screening of individuals with fasting glucose values of 5.6-6.9 mmol/l is needed to identify IPH

Ultrasound derived fetal growth curves for a Jamaican population.

The objective of this study was to develop fetal growth curves and percentile growth charts for a Jamaican population. Four hundred and ninety-nine Jamaican women of African origin were enrolled in a prospective study from the antenatal clinic of the University Hospital of the West Indies, Kingston, Jamaica. Serial ultrasound scans were performed between 14 and 37 weeks gestation to measure fetal growth. The ultrasound measurements performed were biparietal diameter, head and abdominal circumference and femoral length. A total of 2574 ultrasound scans were performed on the 499 women (mean 5.2 per woman). From these data, centiles for fetal growth curves for the four fetal measurements were constructed and percentile tables were created for a Jamaican population. Birthweight varies between ethnic groups and, therefore, so must fetal growth rates. At present, fetal growth in Jamaica is assessed using standards which are based on data derived from Caucasian populations. Fetal growth curves using data from this study would more accurately identify a fetus that is at risk and hence, provide information which could improve obstetric care. These new growth curves should provide data, which will improve obstetric decision making.

Nutritional status of older adults in urban Jamaica.

The aim of the study was to determine the energy intake and nutritional status of a sample of Jamaican adults, and to compare them among different age groups. Measured height and weight data from a survey in Spanish Town, Jamaica, consisting of 2100 adults aged 25-74 years, with 22 per cent over age 60 years, were used to calculate body mass index (BMI). Using BMI cut-off points of 20 and 27, the prevalence of underweight and overweight, respectively, were determined for different age groups. Energy intake was calculated from a food frequency questionnaire from 967 of the respondents. Among males, mean daily energy intake declined from a high of 3681 kcal (15,401 kJ) for 25-29 year-olds, to a low of 2227 kcal (9318 kJ) for those aged 70-74 years. Corresponding numbers among females were 2935 kcal (12,280 kJ) and 1844 kcal (7715 kJ), respectively. Among those aged 65-74 years, 26.9 per cent of males and 50 per cent of females report daily energy intakes of less than 1600 kcal (6694 kJ) (below the lowest recommended dietary allowance (RDA)), compared to 4.5 and 13.7 per cent of males and females aged 25-34 years. While there are moderate declines in the prevalence of overweight, the prevalence of male underweight increased from 4 per cent among 50-54 year-olds to over 35 per cent among those 65 years and older; and among females the corresponding numbers are from 2 per cent to 10 per cent. All trends with age were significant (p < 0.005). There are significant declines in energy intake, and alarming increases in the prevalence of underweight with increasing age among males. These results are cause for concern and further research in this area is warranted.