The haematology of Jamaicans: red cell indices in HbAA, HbAS, HbAC, and HbA-HPFH genotypes.

Based in the parish of Manchester in central Jamaica, the Manchester Project offered free detection of haemoglobin genotype to senior classes in 15 secondary schools between 2008 and 2013. Restricting the database to 15,103 students aged 15.0-19.9 years provided an opportunity to examine the red cell characteristics of the different haemoglobin genotypes, including normal (HbAA) in 85.0%, the sickle cell trait (HbAS) in 9.7%, HbC trait (HbAC) in 3.5% and hereditary persistence of foetal haemoglobin (HbA-HPFH) in 0.4%. Compared to the normal HbAA phenotype, HbAS had significantly increased mean cell haemoglobin concentration (MCHC), red cell count (RBC), and red cell distribution width (RDW) and decreased mean cell volume (MCV) and mean cell haemoglobin (MCH), these differences being even more marked in HbAC. Compared to HbAA, the HbA-HPFH had significantly increased RDW, but there were no consistent differences in other red cell indices, and there were no significant differences in haematological indices between the two common deletion HPFH variants, HPFH-1 and HPFH-2. Although these changes are unlikely to be clinically significant, they contribute to an understanding of the haematological spectrum of the common haemoglobin genotypes in peoples of African origin.

The Association of Early Life Factors with Body Composition in Peripubertal Jamaican Children / Asociación de los Factores de los Primeros Años de Vida con la Composición Corporal de los Niños Jamaicanos Peripúberes

ABSTRACT Objective: To explore the relationships among early life factors (ie maternal weight, height and body mass index, child's birthweight, birth length and ponderal index) and body composition in peripubertal Jamaican children. Methods: One hundred and seventy-six healthy Jamaican children, 9-12 years of age were recruited from a longitudinal cohort. Their birth anthropometric and maternal anthropometric data during pregnancy were available for analysis. Measurements of anthropometry and body composition using bioelectrical impedance analysis were made. Pubertal stage was also recorded. Multiple linear regression analyses were performed. Results: Adjusting for age and gender of the children, maternal weight and birthweight were positively associated with child's weight, height, body mass index (BMI) and lean body mass (LBM); maternal height was positively associated with child's height and LBM; and maternal BMI was positively associated with BMI and LBM of the child. Also, birth length was positively related to child's height. When child's current height was further added to the models, child's LBM was no longer associated with weight and height of mothers and birthweight but was related to child's current height (p = 0.00). Adjustment for pubertal stage in all models did not significantly change these associations. Conclusion: In this Afro-Caribbean cohort, we found that higher maternal weight, height and birthweight are associated with greater height and LBM in the peripubertal period.

RESUMEN Objetivo: Explorar las relaciones entre los factores de los primeros años de vida (ie el índice de masa corporal materno (IMC) y la altura, el peso al nacer del niño, su longitud al nacer y el índice ponderal) y la composición corporal en niños jamaicanos peripúberes. Métodos: Ciento setenta y seis niños jamaicanos sanos, de 9 a 12 años de edad fueron reclutados de una cohorte longitudinal. Sus datos antropométricos de nacimiento y los datos antropométricos maternos durante el embarazo estaban disponibles para el análisis. Las mediciones de la antropometría y la composición corporal se realizaron usando el análisis de impedancia bioeléctrica. El período de pubertad fue también registrado. Se hicieron análisis de regresión lineal múltiple. Resultados: El ajuste por edad y el género de los niños, el peso materno y el peso al nacer estuvieron positivamente asociados con el peso del niño, la altura, IMC, y la MCM; la altura materna estuvo positivamente asociada con la altura y la MCM del niño; y el IMC materno estuvo positivamente asociado con el IMC y la MCM. Asimismo, la longitud al nacer estuvo relacionada positivamente con la altura del niño. Cuando la altura actual del niño se añadió a los modelos, la MCM del niño no se relacionó ya con el peso y la estatura de las madres y el peso al nacer, sino con la altura actual del niño (p = 0.00). El ajuste por etapa puberal en todos los modelos no cambió significativamente estas asociaciones. Conclusión: En esta cohorte afrocaribeña, encontramos que un mayor peso materno, altura, y peso al nacer se asocian con mayor altura y MCM en el período peripuberal.

Parental childhood growth and offspring birthweight: pooled analyses from four birth cohorts in low and middle income countries.

OBJECTIVE: Associations between parental and offspring size at birth are well established, but the relative importance of parental growth at different ages as predictors of offspring birthweight is less certain. Here we model parental birthweight and postnatal conditional growth in specific age periods as predictors of offspring birthweight. METHODS: We analyzed data from 3,392 adults participating in four prospective birth cohorts and 5,506 of their offspring. RESULTS: There was no significant heterogeneity by study site or offspring sex. 1SD increase in maternal birthweight was associated with offspring birthweight increases of 102 g, 1SD in maternal length growth 0-2 year with 46 g, and 1SD in maternal height growth Mid-childhood (MC)-adulthood with 27 g. Maternal relative weight measures were associated with 24 g offspring birth weight increases (2 year- MC) and 49 g for MC-adulthood period but not with earlier relative weight 0-2 year. For fathers, birthweight, and linear/length growth from 0-2 year were associated with increases of 57 and 56 g in offspring birthweight, respectively but not thereafter. CONCLUSIONS: Maternal and paternal birthweight and growth from birth to 2 year each predict offspring birthweight. Maternal growth from MC-adulthood, relative weight from 2-MC and MC-adulthood also predict offspring birthweight. These findings suggest that shared genes and/or adequate nutrition during early life for both parents may confer benefits to the next generation, and highlight the importance of maternal height and weight prior to conception. The stronger matrilineal than patrilineal relationships with offspring birth weight are consistent with the hypothesis that improving the early growth conditions of young females can improve birth outcomes in the next generation.

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.

Body composition in pregnancies of adolescents and mature women and the relationship to birth anthropometry.

OBJECTIVE: To investigate differences in body composition between adolescent girls and mature women during pregnancy and the relationship to newborn anthropometry. DESIGN: A prospective study. SETTING: The antenatal clinic at the University Hospital of the West Indies, Kingston, Jamaica. SUBJECTS: Four hundred and twenty-five women were invited to join the study. Three hundred and sixty-one women (84.9%) completed the study. INTERVENTIONS: Study participants were divided into two groups: adolescents and mature women, who were all less than 15 weeks pregnant and had no systemic illness at the time of entry into the study. A questionnaire was administered which retrieved information on demographics, age, marital status, menstrual history, parity, socio-economic status, medical history and smoking/drinking habits. Anthropometric measurements including weight, height, triceps, biceps, subscapular and suprailiac skinfolds, as well as blood pressure measurements and urine analysis were performed at the first antenatal visit and repeated at 15, 25 and 35 weeks gestation. Anthropometric measurements of the newborn were performed at birth. RESULTS: There were significant differences between anthropometry and skinfold thickness at the first antenatal visit between the adolescents and the mature women where the adolescents had lower measurements compared to the mature women. In the newborn anthropometry, the only significant difference seen was in the triceps skinfold thickness and the mid-upper arm circumference where the newborn of the adolescents had significantly smaller values (P=0.04; P=0.02, respectively). The percentage fat, fat mass and lean body mass were significantly lower in the adolescent compared to the mature women (P<0.0001), both at the first antenatal visit and at 35 weeks gestation. A greater gain was seen in these measurements throughout the pregnancy in the adolescents (P<0.0001). Linear regression analyses showed that the gain in lean body mass was the most important predictor of birth anthropometry. CONCLUSION: Body composition differs in pregnancy between adolescents and mature woman, and if adequate weight and lean body mass are attained, it impacts positively on birth size irrespective of age.

Growth curves for normal Jamaican neonates / Curvas de crecimiento en los neonatos jamaicanos normales

The aim of this study was to provide standards for the assessment of birthweight, head circumference and crown-heel length for normal, singleton newborns of predominantly West African descent. Data were collected for 10 482 or 94of all recorded births in Jamaica during the two-month period September 1 to October 31, 1986. After editing procedures, data were available for 6178 (birthweight), 5975 (head circumference), and 5990 (crown-heel length). The data presented in tables and growth curves include birthweight, head circumference and crown-heel length for males and females separately, for gestational ages 30-43 weeks. Data sets from the University Hospital of the West Indies in 1990 and 1999 were used to explore the possibility of secular change over the period 1986-1999. In conclusion, these ethnic and gender-specific growth curves are based on the most extensive dataset currently available in Jamaica for babies of West African descent.

Growth curves for normal Jamaican neonates.

The aim of this study was to provide standards for the assessment of birthweight, head circumference and crown-heel length for normal, singleton newborns of predominantly West African descent. Data were collected for 10 482 or 94% of all recorded births in Jamaica during the two-month period September 1 to October 31, 1986. After editing procedures, data were available for 6178 (birthweight), 5975 (head circumference), and 5990 (crown-heel length). The data presented in tables and growth curves include birthweight, head circumference and crown-heel length for males and females separately, for gestational ages 30-43 weeks. Data sets from the University Hospital of the West Indies in 1990 and 1999 were used to explore the possibility of secular change over the period 1986-1999. In conclusion, these ethnic and gender-specific growth curves are based on the most extensive dataset currently available in Jamaica for babies of West African descent.

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.

Fetal growth is directly related to maternal anthropometry and placental volume.

OBJECTIVE: To describe the influence of maternal weight and weight gain, placental volume and the rate of placental growth in early pregnancy on fetal dimensions measured sonographically. DESIGN: In a prospective study, 712 women were recruited from the antenatal clinic of the University Hospital of the West Indies. Data analysis was confined to 374 women on whom measurements of the placental volume at 14, 17 and 20 weeks gestation were complete. Measurements of maternal anthropometry and fetal size (by ultrasound) were performed. Weight gain in pregnancy between the first antenatal visit (8-10 weeks) and 20 weeks gestation, and the rate of growth of the placenta between 14-17 and 17-20 weeks gestation were calculated. MAIN OUTCOME MEASURES: Fetal anthropometry (abdominal and head circumferences, femoral length, and biparietal diameter) at 35 weeks gestation. RESULTS: Lower maternal weight at the first antenatal visit was associated with a significantly smaller placental volume at 17 and 20 weeks gestation (P<0.002 and <0.0001 respectively). In all women, maternal weight gain was directly related to fetal anthropometry. Placental volume at 14 weeks gestation and the rate of growth of the placenta between 17 and 20 weeks gestation were significantly related to all four fetal measurements. CONCLUSION: This study has provided evidence that both placental volume, and the rate of placental growth may influence fetal size. These effects are evident in the first half of pregnancy, and appear to be mediated through maternal weight and weight gain.

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.

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

Shortness at birth is associated with insulin resistance in pre-pubertal Jamaican children.

AIM: To investigate the relationship between anthropometry at birth and glucose/insulin metabolism in childhood using the response to an oral glucose challenge. METHOD: Four hundred mother/child pairs on whom gestational and birth data were available were studied. After an overnight fast, anthropometric measurements were made on the children and an oral glucose tolerance test performed. The plasma concentrations of insulin, pro-insulin and 32-33 split pro-insulin were also measured. Skinfold thicknesses were used to calculate percentage body fat and fat mass was derived from the percentage fat and absolute weight. RESULTS: The mean age of the children was 8 y (range 7.5-10.5), and six exhibited impaired glucose tolerance based on WHO criteria. Insulin concentration 120 min after the oral glucose load (a measure of insulin resistance) was inversely related to length at birth (P<0.005). The children who were in the shortest quartile at birth and were heaviest at 8 y old had the highest insulin concentration. CONCLUSION: Shortness at birth is related to insulin resistance. Such insensitivity to the action of insulin is greater in heavier children.

First trimester maternal weight influences foeto-placental growth [abstract]

OBJECTIVE: To examine the effect of maternal weight on foetoplacental growth. METHODS: Seven hundred and twelve women attending their first antenatal clinic visit at the University Hospital of the West Indies, Kingston, Jamaica, were invited to join a perspective study. Maternal anthropometry and blood pressure were performed. Abdominal ultrasound was performed at 14, 17, 20, 25, 30, and 35 weeks of gestation to determine placental and foetal growth. Placental volume was measured at the first 3 visits and foetal biparietal diameter, femoral lenght, and head and abdominal circumfrence were measured at all 6 visits. Two groups of women were created based on their first trimester weight (<55kg and o55kg) for comparison. A ratio of placental volume to foetal abdominal circumference was created and the rate of growth examined between 14 to 17 and 17 to 20 weeks' gestation. RESULTS: Women with lower maternal weight in the first trimester had significantly smaller placental volumes at 17 and 20 weeks' gestation (p<0.03 and P<0.0001, respectivley). Lighter women had foetuses with a smaller head circumference and femoral length noted at 35 weeks gestation (p<0.01 and p<0.03, respectively). A significant relation with with foetal abdominal circumferences was seen as early as 25 weeks' gestation. The rate of foeto-placental growth when first examined at 14 weeks was similar between the two groups of women. However, in the lighter women, relative growth of placenta between 14 to 17 and 17 to 20 weeks' gestation was less than in the heavier women, suggesting poorer relative placental growth in lighter mothers. CONCLUSION: Maternal weight is an important contributor to foeto-placental growth. Lighter women are more likely to have poorer placental growth and hence smaller foetuses. (AU)

Second-trimester placental volume and infant size at birth.

OBJECTIVE: To investigate the ability of second-trimester placental volume measured sonographically to predict birth size. METHODS: A total of 712 women were recruited from the antenatal clinic of the University Hospital of the West Indies; 561 fulfilled the study criteria and progressed to delivery. Placental volume and fetal anthropometry (biparietal diameter, head and abdominal circumferences, and femoral length) were measured sonographically at 14, 17, and 20 weeks. The main outcome measures were infant birth and placental weights, length, head, chest, and abdominal circumferences at birth. RESULTS: Placental volume in the second trimester was positively associated with all birth measurements. Of the fetal measurements at 14 and at 17 weeks, head circumference was the strongest predictor of birth weight (B [slope of the regression line] =.095, P =.014 at 14 weeks; B =.118, P =.012 at 17 weeks), but at 20 weeks, abdominal circumference was the strongest. However, at each age, placental volume was the strongest determinant of birth weight, and improved the prediction based only on fetal measurements. The odds ratio for low birth weight (under 2500 g) increased by 1.68 (95% confidence interval 1.05, 2.69, P = 0.03) for every standard deviation decrease in placental volume at 14 weeks' gestation. CONCLUSION: The present study suggests that low birth weight was often preceded by small placental volume in the second trimester. Placental volume may be a more reliable predictor of size at birth than fetal measurements, and may be useful in early identification of the fetus at risk in the perinatal period.

Fetal growth and cardiovascular risk factors in Jamaican schoolchildren.

OBJECTIVE: To determine relation between schoolchildren's blood pressure, glycated haemoglobin level, and cholesterol concentration and their anthropometry, socioeconomic status, and birth measurements. DESIGN: Retrospective cohort study. SETTING: 27 schools closest to University Hospital of the West Indies, Kingston, Jamaica. SUBJECTS: 2337 children aged 6-16 years who were born at university hospital were recruited, and their birth records were recovered: 1610 had suitable records, 659 had records including birth length, and 610 of these were prepubertal. MAIN OUTCOME MEASURES: Blood pressure, glycated haemoglobin level, serum cholesterol concentration, anthropometry at birth, current anthropometry, and socioeconomic status. RESULTS: Multiple regression analysis showed that children's systolic blood pressure was inversely related to their birth weight (P < 0.0001) and directly related to their current weight. Glycated haemoglobin level was higher in children with thicker triceps skinfolds (P < 0.001) and who had been shorter at birth (P = 0.003). Serum cholesterol concentration was inversely related to current height (P = 0.001) and to length at birth (P = 0.09) and was directly related to triceps skinfold thickness and higher socioeconomic status (P < 0.001). CONCLUSIONS: Blood pressure in childhood was inversely related to birth weight and directly to current weight. Glycaemic control and serum cholesterol were related to short length at birth, height deficit in childhood, and childhood obesity.