Ellisras Longitudinal Study 2017: The relationship between waist circumference, waist-to-hip ratio, skinfolds and blood pressure among young adults in Ellisras, South Africa (ELS 14).

BACKGROUND: Obesity and hypertension are major risk factors for non-communicable diseases in the world today. The relationship between indicators of obesity and blood pressure needs attention in the rural South African population. AIM: This study examined the relationship between anthropometric parameters and blood pressure (BP) among young adults in the Ellisras rural area of South Africa. METHODS: A total of 742 (365 females and 377 males) young adults aged 22 to 30 years, who were part of the Ellisras Longitudinal Study (ELS), participated in the research. Anthropometric and BP measurements were taken using the protocol of the International Society for the Advancement of Kinanthropometry (ISAK). Linear regression was used to determine the relationship between anthropometric parameters and BP. The risk of developing hypertension among young Elisras adults was evaluated using logistic regression. RESULTS: The results indicted a higher but on-significant prevalence of hypertension in men (2.7%) than women (2.4%). Linear regression showed a significant positive (p < 0.05) association between waist circumference and systolic BP (ß = 0.273, 95% CI: 0.160-0.386), even after being adjusted for age and gender (ß = 253, 95% CI: 0.127-0.343). The risk for developing hypertension was significant ( p < 0.05) for waist circumference (OR = 2.091, 95% CI: 1.129-3.871) after adjustment for age and gender. CONCLUSIONS: Of all anthropometric parameters, waist circumference was most significantly associated with BP ( p < 0.05). Anthropometric indicators of obesity were strong predictors of hypertension among young adults in the Ellisras rural area.

Waist circumference percentiles of black South African children aged 10 - 14 years from different study sites

Background. Waist circumference (WC) is a useful predictor of cardiometabolic risk in children. Published data on WC percentiles of children from African countries are limited.Objectives. To describe age- and sex-specific Wpercentiles in black South African (SA) children from different study sites, and compare these percentiles with median WCpercentiles of African-American (AA) children.Methods. Secondary data on WC for 10 - 14-year-old black SA children (N=4 954; 2 406 boys and 2 548 girls) were extracted from the data sets of six studies. Smoothed WC percentile curves for boys and girls were constructed using the LMS method. The 50th percentile for age- and sex-specific WC measurements was compared across study sites and with AA counterparts.Results. Girls had higher WC values than boys from the 50th to 95th percentiles at all ages. The 50th WC percentiles of all groups of SA children combined were lower than those of AA children. When SA groups were considered separately, Western Cape children had median WC values similar to AA children, while rural Limpopo children had the lowest WC values. The 95th percentiles for Western Cape girls exceeded the adult cutoff point for metabolic syndrome (WC ≥80 cm) from age 11years.Conclusions. The differences in WC values for 10 - 14-year-old children across the six study sites highlight the need for nationally representative data to develop age-, sex- and ethnic-specific WC percentiles for black SA children. The results raise concerns about high WC among Western Cape girls

The risk of metabolic syndrome as a result of lifestyle among Ellisras rural young adults.

The study aimed to investigate the association between metabolic syndrome (MetS) and lifestyle risk factors among Ellisras adults. A cross-sectional study was conducted on 624 adults (306 males and 318 females). MetS was defined according to the criteria of the International Diabetes Federation. The prevalence of MetS was 23.1% (8.6% males and 36.8 % females). Females appeared to have higher mean values for waist circumference (WC), fasting blood glucose (FBG), total cholesterol (TCHOL) and low-density lipoprotein cholesterol (LDL-C), while males had high mean values for high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), systolic blood pressure (SBP) and diastolic blood pressure (DBP). No significant age and gender differences were observed for dietary intake. Significantly more females (51.9%) presented with increased WC than males (4.6%). Participants who had a high dietary energy intake were significantly less likely to present with larger WC (OR: 0.250 95% CI [0.161; 0.389]), low HDL-C (OR: 0.306 95% CI [0.220; 0.425]) and high LDL-C (OR: 0.583 95% CI [0.418; 0.812]) but more likely to present with elevated FBG (OR: 1.01 95% CI [0.735; 1.386]), high TCHOL (OR: 1.039 95% CI [0.575; 1.337]), high TG (OR: 1.186 95% CI [0.695; 2.023]) and hypertension (OR: 5.205 95% CI [3.156; 8.585]). After adjusting for age, gender, smoking, and alcohol status, high energy intake was more than two times likely to predict MetS in adults with a large WC (OR: 2.766 95% CI [0.863; 3.477] and elevated FBG (OR: 2.227 95% CI [1.051; 3.328]). Therefore, identifying groups that are at an increased risk and those that are in their early stages of MetS will help improve and prevent the increase of the MetS in the future.

Performance of blood pressure to height ratio as a screening tool for elevated blood pressure in rural children: Ellisras Longitudinal Study.

There are complications in diagnosing hypertension in children and adolescents due to variation of blood pressure (BP) values to age, gender and height. This study was aimed at assessing whether the performance of BP-to-height ratio (BPHR) can be an effective tool for screening prehypertension and hypertension in Ellisras Longitudinal Study (ELS) children aged between 6 and 17 years. A number of the 9002 children aged 6-17 years who were part of the ELS underwent height and BP measurements using standard procedures. Receiver-operating characteristic curve was used to assess the accuracy of BPHR to screen children with prehypertension and hypertension. The optimal systolic BPHR (SBPHR) and diastolic BPHR (DBPHR) cut-off points for hypertension were determined. Sensitivity/specificity, positive predictive values and negative predictive values were calculated. The optimal thresholds for defining prehypertension was 0.77 in children aged 6-10 years and 0.73 in adolescents aged between 11 and 17 years for systolic BPHR and 0.55 in children and 0.53 in adolescents for diastolic BPHR, respectively. The corresponding values for hypertension stage 1 were 0.76 and 0.73 for SBPHR and 0.50 and 0.58 for DBPHR, respectively. BPHR can be used as an effective tool for screening both prehypertension and hypertension in ELS children aged 6-17 years.

The relationship between BMI and dietary intake of primary school children from a rural area of South Africa: The Ellisras longitudinal study.

OBJECTIVES: To investigate the relationship between dietary intake and BMI of primary school children from a rural area of South Africa cross-sectionally. Both under and over nutrition remain major health problems in South Africa. In rural areas, where especially undernutrition leads to child morbidity and mortality, determinants should be detected. METHODS: Data was used from 825 children (421 boys, 404 girls), aged 6-12 years, participating in the Ellisras Longitudinal Growth study. Height and weight were measured in accordance with the protocol of the International Society for the Advancement of Kinanthropometry. Internationally recommended cut-off points for body mass index (BMI) were used. Dietary intake was measured using the 24 h recall method. In general, boys and girls from Ellisras had dietary intake levels lower than or according to dietary guidelines. RESULTS: A singular linear regression model showed a significant association between monounsaturated fat and BMI. The multiple model demonstrated that total fat (B = 0.05, CI: 0.019-0.082), monounsaturated fat (B = -0.093, CI: -0.160 to -0.026) and polyunsaturated fat (B = 0.056, CI: 0.09-0.02) predict BMI. CONCLUSION: This study supports previous findings about BMI and dietary trends in rural areas of South Africa. Despite low fat intake of the subjects, this macronutrient appeared to predict BMI most strongly. More research is needed; however, to further examine how healthy their lifestyle is nowadays with respect to diet and into what extent the nutrition transition has reached this area.

Development and tracking of body mass index from preschool age into adolescence in rural South African children: Ellisras Longitudinal Growth and Health Study.

The purpose of this observational prospective cohort study was to investigate the development and tracking of body mass index (BMI) of Ellisras rural children from preschool age into late adolescence from the Ellisras Longitudinal Growth and Health Study. Heights and weights of children were measured according to the standard procedures recommended by the International Society for the Advancement of Kinanthropometry twice a year from 1996 to 2003. In total, 2,225 children--550 preschool and 1,675 primary school--aged 3-10 years (birth cohorts 1993 to 1986) were enrolled at baseline in 1996 and followed through out the eight-year periodic surveys. In 2003, 1,771 children--489 preschool and 1,282 primary school--were still in the study. The prevalence of overweight was significantly higher among girls (range 1.6-15.5%) compared to boys (range 0.3-4.9%) from age 9.1 years to 14.9 years. The prevalence of thinness (severe, moderate, and mild) ranged from 7.1% to 53.7% for preschool children and from 8.0% to 47.6% for primary school children. Both preschool and primary school children showed a significant association between the first measurements of BMI and the subsequent measurement which ranged from B=0.2 (95% confidence interval [CI] 0.1-0.4) to B=0.8 (95% CI 0.6-0.9) for preschool and B=0.2 (95% CI 0.1-0.3) to B=0.7 (95% CI 0.6-0.8) for primary children. A significant tracking of BMI during 4-12 years of life was more consistent for preschool children (B=0.6 (95% CI 0.6-0.7) and for primary school children (B=0.6 (95% CI 0.5-0.6). Investigation of nutritional intake and physical activity patterns will shed light on how healthy these children are and their lifestyle.

Relationship between fat patterns, physical fitness and blood pressure of rural South African children: Ellisras Longitudinal Growth and Health Study.

The present study investigated the relationship between blood pressure (BP), fat patterns and fitness parameters of Ellisras children aged 7-13 years. Furthermore, an assessment of body fat patterns was done to determine the subjects with the highest risk of overweight, hypertension and waist-to-hip ratio above the 90th percentile. Data were collected from 1,817 subjects (938 boys and 879 girls), aged 7-13 years, participating in the Ellisras Longitudinal Study. Anthropometric measurements were taken according to the standard procedure of the International Society for the Advancement of Kinanthropometry. The EUROFIT test items were used to test the physical fitness of 1,192 subjects (634 boys and 558 girls). Obesity was defined using the international recommended cutoff points for body mass index (BMI) in children. Hypertension was defined as the occurrence of BP levels greater or equal to the 95th percentile of height- and sex-adjusted reference levels. The prevalence of hypertension ranged from 1 to 11.4% and that of overweight 0.6-4.6%. Waist girth, BMI, triceps and subscapular skinfold showed significant (P<0.001-0.05) correlation with other fat pattern parameters (r ranging from -0.157 to 0.978) compared with significant correlations (P<0.001-0.05) with BP (r ranging from -0.071 to 0.164). Children with waist girth greater than the 90th percentile are more likely to have multiple risk factors than the children with a waist girth that is less than or equal to the 90th percentile. Longitudinal studies should verify whether changes in waist girth and skinfolds will indicate changes in cardiovascular risk factors during growth.

Somatotype and blood pressure of rural South African children aged 6-13 years: Ellisras longitudinal growth and health study.

BACKGROUND: Physique has been useful in assessing the outcome of underlying growth and maturity processes, which leads to a better understanding of variation in child and adult health. However, a high endomorphy rating has been associated with hypertension in adults, posing a serious threat to their health status, while receiving little attention in children. AIM: The study examined the association between somatotypes, body mass index (BMI) and blood pressure (BP) in 6-13-year-old rural children, in Ellisras, South Africa. SUBJECTS: A total of 1902 subjects (980 boys and 922 girls) aged 6-13 years were studied as part of the Ellisras Longitudinal Study. Height, weight, four skinfold sites, two breadths, and two girths were measured according to the International Society for the Advancement of Kinanthropometry (ISAK). The Heath-Carter method of somatotyping was used, together with internationally recommended cut-off points for BMI in children. Hypertension, defined as the average of three separate BP readings, where the systolic or diastolic BP is greater than or equal to the 95th percentile for age and sex, was determined. RESULTS: The prevalence of hypertension ranges from 1 to 5.8% in boys and 3.4-11.4% in girls. The prevalence of overweight ranges from 1.1 to 2.9% in boys and 0.6-4.6% in girls. Systolic BP and BMI showed a significant positive correlation at age 6 years (r = 0.436) and 10-13 years (r = 0.180-0.246 in boys and r = 0.221-0.271 in girls). Diastolic BP showed an insignificant correlation with the BMI and somatotype components in boys and girls. CONCLUSION: A significant association exists between BP and BMI, and ectomorphy components even after being adjusted for age, gender and height. The need to manage hypertensive individuals is evident in this sample to combat this chronic disease from an early age. Follow-up studies should investigate the relationship between BP and the dietary intake of these children.

The association of fat patterning with blood pressure in rural South African children: the Ellisras Longitudinal Growth and Health Study.

BACKGROUND: Hypertension is one of the major causes of death in developed and underdeveloped nations. Essential hypertension and obesity may have their inception in childhood, with little data in African children to support these findings. Objectives were to determine the prevalence of overweight and hypertension in rural children in South Africa. Additionally, the association between fat-patterning ratios and blood pressure (BP) was investigated. METHODS: Data were collected from 1884 subjects (967 boys and 917 girls), aged 6-13 years, participating in the Ellisras Longitudinal Study. Height; weight; and triceps, biceps, subscapular, and suprailiac skinfolds were measured according to the protocol of the International Society for the Advancement of Kinanthropometry. Skinfold ratio was used as an indicator of the central pattern of body fat. Internationally recommended cut-off points for body mass index (BMI) were used. Hypertension, defined as the average of three separate BP readings where the systolic BP or diastolic BP is >or=95th percentile for age and sex, was determined. RESULTS: The prevalence of hypertension ranged from 1 to 5.8% for boys and 3.1 to 11.4% for girls, and that of overweight from 1.1 to 2.9% for boys and 0.6 to 4.6% for girls. The association between high systolic BP and high BMI was -3.0, while that for high diastolic BP and high BMI was -0.68. CONCLUSIONS: The prevalence of hypertension is evident from the age 6 years for girls, while that of overweight was low. Overweight became evident from the age 10 to 13 years for both sexes. A significant association between high diastolic BP and high BMI was noted, while children with low BMIs were less likely to be hypertensive. Investigating habitual physical activity, fitness and dietary patterns will shed more light on the association of fat patterning and BP in this population.

Body composition and physical fitness of undernourished South African rural primary school children.

OBJECTIVE: The purpose of this study was to determine the relationships between the body composition characteristics, body mass index (BMI), sum of skinfolds (SSF), % body fat (%BF), fat-free mass (FFM) and waist-to-hip ratio (WHR), and nine physical fitness items in undernourished rural primary school children in Ellisras, South Africa. DESIGN: A cross-sectional study. SETTING: The study consisted of 462 boys and 393 girls who were aged 7-14 y. MEASUREMENTS: Five body composition measures were assessed: BMI, SSF, %BF, FFM and WHR. Nine physical fitness test items were assessed: standing long jump, bent arm hang, sit-ups, 10 x 5 m shuttle run, 50 m sprint, 1600 m run, flamingo balance, sit and reach, plate tapping. RESULTS: BMI was highly correlated with FFM (r = 0.7, P < 0.001). In line with findings from Western countries, regression coefficients (B) showed that children with higher BMI or SSF performed worse in bent arm hang (girls, B = -0.84, P < 0.001, and B = -0.06, P = 0.02, respectively) and in 1600m run (B = 6.68, P < 0.001). BMI was significantly associated with flamingo balance (B = 0.26, P = 0.04). WHR was positively associated with bent arm hang (B = 9.37, P = 0.03), and inversely with sit and reach (B = -7.48, P = 0.01). In contrast, significant relationships were found between BMI and standing long jump (B = 0.74, P = 0.04), sit and reach (B = 0.51, P < 0.001), flamingo balance (B = 0.26, P = 0.04) and plate tapping (B = -19, P = 0.01). SSF was significantly associated with sit and reach (B = 0.04, P = 0.03). Significant inverse associations were found between FFM and bent arm hang (girls, B = -0.06, P = 0.05), 1600 m run (girls, B = -2.33, P = 0.003) and 50 m run (boys, B = -0.11, P = 0.006). FFM was significantly associated with standing long jump (boys, B = 0.99, P < 0.001; girls, B = 0.73, P < 0.001), flamingo balance (B = 0.17, P < 0.001), and with sit and reach (boys, B = 0.59, P = 0.03). CONCLUSION: In the present study in undernourished children, body composition was significantly related to physical fitness, but not always in the expected direction. It is therefore important to note that in this population, BMI should not be interpreted as a measure of fatness/overweight, but rather as an indicator of muscle mass.

Nutrition related knowledge and practices of hypertensive adults attending hypertensive clinics at Day Hospitals in the Cape Metropole.

The aim of this study was to determine nutrition knowledge and dietary practices of hypertensive adults attending hypertensive clinics at Day Hospitals in the Cape Metropole. Ten Day Hospitals were randomly selected from a total of 31 Day Hospitals and the first participants attending the hypertension clinics per day were recruited. A total of 85 participants were evaluated. The weight, height, waist and hip circumference of each participant was measured, as well as their blood pressure. Knowledge of dietary intake was obtained by completing a questionnaire, during an interview with the patient. Knowledge regarding salt usage indicated that a large percentage (34.1%) of participants believed that flavour enhancers like Aromat or Fondor could safely be used instead of table salt. Furthermore, 23.5% reported that tinned and smoked meat or fish have a low sodium (salt) content. Fruit and vegetables were perceived as having a positive effect on hypertension by 74.1% of participants. However, only 15% of the group knew that the recommendation for their usage was five or more servings per day. Only 12.9% of participants in this study had a normal weight (body mass index (BMI) < 25), 25.9% were overweight (BMI 25 - 29.9) and 61.2% were obese (BMI > or =30); 84.7% recognized the association between obesity and hypertension. A large waist circumference (> 88 cm in women; 102 cm in men) was found in 61.2% of participants, however, only 18.2% of black men had such a measurement. Uncontrolled blood pressure readings (> 140/90 mm Hg) were found in 61.2% of these patients at the hypertension clinics.

Stability of somatotypes in 4 to 10 year-old rural South African girls.

In 1996, a mixed Ellisras longitudinal study (ELS) was initiated to assess the stability of somatotypes in 408 girls who comprised 99 pre-school and 309 primary school children in Ellisras rural area in the Northern Province of South Africa. The children's somatotype was assessed using the Heath-Carter anthropometric method. Anthropometric dimensions were taken according to the protocol of the International Society for the Advancement of Kinanthropometry (ISAK). The most stable pre-school and primary school girl had migratory distances (MDs) of 2.6 and 3.4, respectively, while the least stable pre-school and primary school girl had MDs of 17.9 and 24.4, respectively. The mean somatotype of the pre-school children was mesomorph-ectomorph throughout the complete age range, while the mean somatotype of primary school girls was mesomorph-ectomorph for all the age groups except for the 9.5 years group at which it was in the balanced ectomorph. The inter-age partial correlations for endomorphy and ectomorphy were high and significant, but insignificant with regard to mesomorphy.

Growth and nutritional status of rural South African children 3-10 years old: The Ellisras growth study.

This study presents cross-sectional data from an ongoing mixed-longitudinal study of growth of rural children from Ellisras, South Africa. The physical growth and nutritional status of 1,335 children (684 boys, 651 girls), 3-10 years of age, was determined using standard anthropometric techniques. Weight-for-age, height-for-age, and weight-for-height were expressed as Z-scores of the NHANES I and II or NCHS reference sample. A Z-score of less than -2 was used as the cut-off point to determine the prevalence of stunting and wasting. Mean heights increased parallel to the 50(th) centile up to 6 years of age, thereafter both sexes diverged from the NHANES reference by approximately 0.5 cm per year. Mean weights followed a more consistent pattern from 3-7 years for both sexes, which was parallel to just below the 10(th) centile, but diverged between 8 and 10 years of age. Z-scores of weight-for-height in both sexes varied between -1 to -2 throughout the age range and BMI values were lower than the 5(th) centile of NHANES, indicating a significant amount of wasting within the sample. The sample exhibited a high prevalence of stunting, rising from less than 10% at 7 years to more than 30% by 10 years of age. Increments of the mean heights and weights indicate that the effects of stress may be a gradually accumulating process and that the growth increments of these children became increasingly poor in contrast to those of the reference sample. Since stunting in childhood is permanent, it may lead to a loss of physical work capacity in adulthood. Therefore, further investigation of the cause of poor growth among these rural children is imperative. Am. J. Hum. Biol. 12:42-49, 2000. Copyright 2000 Wiley-Liss, Inc.

Obesity: does it occur in African children in a rural community in South Africa?

BACKGROUND: Total body fatness and a centripetal fat patterning are recognized as risk indicators of cardiovascular disease in adulthood. In this study, the development of these risk factors in rural South African children during the preschool years and first years of formal schooling is explored. METHOD: The initial cross-sectional data from the Ellisras Longitudinal Investigations in Rural Community Children Project, ongoing since 1996, were used, involving 684 boys and 652 girls, aged 3-10 years, in the Ellisras rural community. Overweight was measured using the body mass index (BMI) (kg/m2). Overfatness was based on the sum of the triceps and subscapular skinfold thicknesses. A centripetal fat patterning was measured by the sum of trunk skinfolds relative to limb skinfolds and the ratio of the subscapular to triceps skinfold. Further, the ratio of the subscapular to supraspinale skinfold was used as an indicator of lower body fat patterning. The 85th percentiles of the NHANES III were used as cutoff values for overweight, overfatness and a centripetal fat patterning. RESULTS: At ages 7 and 8 years, mean BMI was statistically significantly higher in males compared to females (P < 0.05). The log transformed supraspinale skinfold thickness was larger in females compared to males at ages 4-7 years; the log transformed subscapular skinfold was larger in girls compared to boys aged 7-10 years. Less clear patterns were found for the extremity skinfolds and the skinfold ratios. Very few children (0-2.5% in males and 0-4.3% in females) had BMI values above the NHANES III 85th percentiles, indicating a very low prevalence of overweight children in the area. About 15% of the males showed overfatness at ages 3-4 years, while low prevalence was found at older ages. CONCLUSION: Few Ellisras rural children had above normal values for BMI, indicating a low prevalence of obesity in this population. In the 3- and 4-year-old group more subjects were found to have excessive fat, as indicated by the sum of the triceps and subscapular skinfold thicknesses.

PIP: Total body fatness and a centripetal fat patterning are risk indicators of cardiovascular disease in adulthood. The development of those risk factors in rural South African children during the preschool years and first years of formal schooling was investigated. Findings are based upon the analysis of initial cross-sectional data from the Ellisras Longitudinal Investigations in Rural Community Children Project, involving 684 boys and 652 girls aged 3-10 years. At ages 7 and 8 years, mean body mass index (BMI) was statistically significantly higher among boys than among girls. The log-transformed supraspinal skinfold thickness was larger in females than in males at ages 4-7 years, and the log-transformed subscapular skinfold was larger in girls than in boys aged 7-10 years. Less clear patterns were found for the extremity skinfolds and skinfold ratios. 0-2.5% of boys and 0-4.3% of girls had BMI values higher than the National Health and Nutrition Examination Survey (NHANES III) 85th percentiles, indicating a very low prevalence of overweight children in the area. About 15% of the boys were overfat at ages 3-4 years, and a low prevalence was observed at older ages.