7,832 research outputs found
The female athlete triad in student track and field athletes
No full textObjectives: To explore the female athlete triad components in university track and field athletes, as well as calculate estimated energy availability. Design: Cross-sectional descriptive study design. Setting and subjects: Sixteen volunteer, white, female track and field athletes were recruited from North-West University. Outcome measures: Athletes completed a demographic, health and sport questionnaire; pathogenic body weight control questionnaire; menstrual history questionnaire; four 24-hour dietary recalls and one three-day diet and exercise record form. Body composition and bone mineral density (BMD) were assessed with dual energy X-ray absorptiometry. The bulimia, drive for thinness and body dissatisfaction subscales of the Eating Disorder Inventory, and the cognitive dietary restraint subscale of the Three-Factor Eating Questionnaire, was used to measure disordered eating behaviour. Estimated energy availability was calculated using a three-day dietary and exercise record form completed by the athlete on three heavy training days. Results: In the total group, 25% had menstrual pattern changes, 62.5% disordered eating behaviour, 73.3% (11/15) low estimated energy availability, and 12.5% reported stress fractures during the past two years. The average estimated energy availability was 18.5 (14.1-40.9) kcal/kg fat-free mass/day. Diet or fat-burning pills were the most popular pathogenic weight-control measures used by 37.5% athletes. Athletes with menstrual pattern changes had lower spine [1.043 (0.975-1.059) vs. 1.166 (1.090-1.234) g/cm2, p-value = 0.043] and femoral neck [0.905 ± 0.045 vs. 1.025 ± 0.027 g/cm2, p-value = 0.042) BMD. Altogether, 87.5% athletes presented with various components of. Conclusion: More than two thirds of this group of student track and field athletes had low estimated energy availability and more than three quarters were classified with various combinations of the components of the female athlete triad
Substitution of sedentary time with light physical activity is related to increased bone density in U.S. women over 50 years old. An iso-temporal substitution analysis based on the National health and Nutrition Examination Survey
No full textU.S. women are ageing. This is causing rises in osteoporosis prevalence and risk of fracture with related increases in health care costs. Replacing sedentary time with light physical activity may represent a cost effective public health solution to osteoporosis in elderly women. The National Health and Nutrition Examination Survey conducted over the period 2003-2006 provided cross-sectional data on bone mineral density and objectively assessed physical activity among 1,052 women aged 50-85 years old. Substitution analysis was applied to estimate increased bone mineral density and reduced osteoporosis for those women replacing 30 min of sedentary time with an equivalent amount of light physical activity. Substitution of 30 min of sedentary time with an equal amount of light physical activity was associated with increased bone mineral density of about 3 mg/cm2 and a 12% reduced risk of osteoporosis in the spine. When considering overweight women and women over 65 years of age, this association was reinforced and it extended to the pelvis, legs and trunk, resulting in a consistent bone mineral density increase of about 3-6 mg/cm2. The substitution of 30 min of sedentary time with an equal amount of light physical activity appears a possible primary prevention method to reduce osteoporosis and related increases in risk of fracture, mortality, and health care costs in women over 50 years old
Disordered eating and menstrual patterns in female university netball players
No full textObjectives: The primary aim of this study was to investigate disordered eating (DE) behavior and menstrual patterns in provincial-to-national level student netball players. The secondary aim was to examine the associations between body composition, energy intake, DE and menstrual patterns in student netball players. Methods: Twenty six Caucasian female netball players from a South African University volunteered to participate in this cross-sectional descriptive study. Height, weight and body composition were measured. Energy intake was assessed with 24-hour recalls and menstrual patterns were assessed with a menstrual history questionnaire. Players also completed an Eating Disorder Inventory (EDI) and an Eating Attitudes Test (EAT-26) to assess DE behavior. Results: Collectively 14 players (54.8%) were identified with DE behavior and scored above the designated cut-off score for the EAT-26 (≥20, n=3), the EDI Body Dissatisfaction subscale (EDI-BD) (≥14, n=7), the EDI Drive for Thinness subscale (EDI-DT) (≥15, n=3), and/or answered “Yes” (n=8) to DE behavioral questions. Eight players (30.8%) reported menstrual irregularities during the past 12 months of which four (15.4%) also reported secondary amenorrhea (absence of ≥3 consecutive menstrual cycles) during training. Five players (19.2%) presented with DE behavior, menstrual irregularity and primary and/or secondary amenorrhea. Reported energy intake was significantly lower in the players with menstrual irregularities and secondary amenorrhea compared to the remaining players (p less than 0.05). Conclusions: Top female student netball players may have suboptimal energy intakes and suffer from DE behavior, menstrual irregularities and secondary amenorrhea. Players and coaches should be aware of these risks and related health and performance consequences
Contribution of commercial infant products and fortified staple foods to nutrient intake at ages 6, 12, and 18 months in a cohort of children from a low socio-economic community in South Africa.
No full textFortification of two staple foods, maize meal and wheat flour (bread), is mandatory,
and commercial infant products are widely available in South Africa. Using a 24
‐
hr
recall, we determined the contribution of these foods towards nutrient intakes at ages
6(
n
= 715), 12 (
n
= 446), and 18 (
n
= 213) months in a cohort of children in a peri
‐
urban community, North West province. On the day of recall, commercial infant prod-
ucts were consumed by 83% of children at 6 months, 46% at 12 months, and 15% at
18 months; fortified staples were consumed by 23%, 81%, and 96%, respectively. For
consumers thereof, commercial infant products contributed 33% energy and 94% iron
intakes at 6 months and 27% energy and 56% iron intakes at 12 months; nutrient
densities of the complementary diet was higher than for nonconsumers for most
micronutrients. For consumers of fortified staples, energy contribution thereof was
11% at 6 months versus 29% at 18 months; at 18 months, fortified staples contrib-
uted
>
30% of iron, zinc, vitamin A, thiamine, niacin, vitamin B6, and folate; at
12 months, nutrient densities of the complementary diet were higher for zinc, folate,
and vitamin B6 but lower for calcium, iron, vitamin A, niacin, and vitamin C than non-
consumers. At ages 12 and 18 months, ~75% of children had low calcium intakes. At
12 months, 51.4% of consumers versus 25.0% (
P
= 0.005) of nonconsumers of forti-
fied staples had adequate intakes (
>
EAR) for all eight fortificant nutrients. However,
despite fortification, nutrient gaps remai
The methodological status of co-authorship networks
No full textA powerful strategy within the study of collaboration
in science is to posit that co-authorship patterns
represent social networks.
It is prerequisite to an application of Social
Network Analysis (SNA) to define the network
entities. A network analysis of the inter-institutional
collaboration in COLLNET on the basis
of co-authorships was conducted. The study reveals
that it is crucial whether the co-authorship
itself is seen as an author's relational property or
as a social event that brings the authors together.
The former possibility is represented by a onemode
network in which each author can be related
to each other author. Quite distinct from
that are two-mode networks, the latter approach.
They consist of two single data sets in which relations
are only possible between different sets.
Different modes of representations require
different network approaches. One is that co-authorship
networks are seen as one-mode networks,
which has the advantage of the application
of a variety of measures. In contrast, twomode
networks, the other option, cannot be analysed
by standard techniques but its distinctive
features demand a new conceptualisation of
measures. In conclusion, the two-mode perspective
is more promising because it allows a dual
perspective on collaboration in science which includes
researchers as well as their scientific output
Physical activity energy expenditure and sarcopenia in black South African urban women
No full textBackground: Black women are believed to be genetically less predisposed to age-related sarcopenia. The objective of this study was to investigate lifestyle factors associated with sarcopenia in black South African (SA) urban women. Methods: In a cross-sectional study, 247 women (mean age 57 y) were randomly selected. Anthropometric and sociodemographic variables, dietary intakes, and physical activity were measured. Activity was also measured by combined accelerometery/heart rate monitoring (ActiHeart), and HIV status was tested. Dual energy x-ray absorptiometry was used to measure appendicular skeletal mass (ASM). Sarcopenia was defined according to a recently derived SA cutpoint of ASM index (ASM/height squared) 2. Results: In total, 8.9% of the women were sarcopenic, decreasing to 8.1% after exclusion of participants who were HIV positive. In multiple regressions with ASM index, grip strength, and gait speed, respectively, as dependent variables, only activity energy expenditure (β = .27) was significantly associated with ASM index. Age (β = -.50) and activity energy expenditure (β = .17) were significantly associated with gait speed. Age (β = -.11) and lean mass (β = .21) were significantly associated with handgrip strength. Conclusions: Sarcopenia was prevalent among these SA women and was associated with low physical activity energy expenditure.</p
Lotka' s Law, Co-authorship and Interdisciplinary Publishing
No full textThe robustness or breakdown of Lotka's law about the frequency distribution of scientific productivity depends on scientific cooperation, counting methods, interdisciplinary publishing and selection methods for sample collections. We have chosen to analyse the relationship using Mandelbrot's equivalent distribution model because this model is sensitive and uses the original data (scores). Five sets of authors and publications, the two sets used by Lotka, a set from High Energy Physics, a set from Microbiology and a set based on applicants to a research programme promoting young researchers have been used. It is shown that even for a sample of authors in High-Energy Physics with extremely strong co-authorship, Mandelbrot's distribution law is robust when complete-normalized (fractional) counting is used whereas complete counting results in a breakdown. In the field of Microbiology with much weaker cooperation, both counting methods result in a breakdown of Mandelbrot's law. Today a field like Microbiology with the corresponding set of journals, probably has a large content of interdisciplinary publishing and therefore no more fulfills the precondition of Lotka's law, that the total production of the authors (sources) is considered. For a set of applicants for the Emmy Noether Programme of the German Research Foundation. Mandelbrot's law breaks down despite the fact that all publications co-authored by the applicants are taken into account. In agreement with Bayes' theorem of conditional probabilities these results lead to the conjecture that any selection process of authors and/or publications causes a breakdown of Mandelbrot's law and, as a consequence Lotka's law
Nutritional status and weight making practices of professional male South African mixed martial arts fighters
No full textMSc (Dietetics), North-West University, Potchefstroom CampusBackground - Weight category combat sport athletes, including mixed martial arts (MMA) fighters, often ‘make weight’ or ‘cut weight’ to fight in lower weight divisions. Common weight-making practices include restriction of food and/or fluid intake and intentional fluid loss/sweating (e.g. sauna). However, a number of these weight-making practices can be detrimental to the performance, health and nutritional status of the fighters. MMA fighters are usually weighed-in 24 hours prior to competition, and then have a subsequent 24 hours to adequately recover/rehydrate for the match (Jetton et al., 2013). Due to the fact that fighters have time to recover/rehydrate, it allows fighters to make use of extreme weight-making practices (i.e. extreme dehydration) to rapidly lose the last bit of unwanted body weight, usually being water weight, in a short time. Although literature is available on the weight making practices of MMA fighters, limited information is available regarding their general nutritional status. Since MMA is a rapidly growing sport with a lot of interest amongst youngsters as well, information on weight-making practices and the nutritional status of these athletes is warranted to enable coaches and allied health professionals to optimise their health and performance. This study therefore aimed to describe the nutritional status (dietary intake and body composition) and weight-making practices of professional male South African MMA fighters. Objectives - The first objective was to determine the nutritional status, including dietary intake and body composition, of professional male South African MMA fighters at baseline (6-weeks prior to competition), 1-week prior to competition and at weigh-in (24-hours prior to weigh-in). The second objective was to determine the weight-making practices of professional male South African MMA fighters prior to weigh-in. The final objective was to determine the hydration status at weigh-in (proxy for fluid loss / extent of fluid weight-making practices).
Methods - Seventeen male South African MMA athletes (aged 28.0±1.0 years, and competitive experience 7.0±1.0 years) participated in this observational study with a descriptive longitudinal study design. Dietary intake was recorded by means of a validated quantified food frequency questionnaire at baseline (6-weeks prior to competition) and again 1-week prior to competition. Anthropometric measures (weight, height and skinfold measurements) were performed by an ISAK level 1 anthropometrist at baseline (6-weeks prior to competition), 1-week prior to competition, and at weigh-in (24-hours prior to weigh-in for weight). A previously validated weight-making practices questionnaire was adjusted and administered to the MMA athlete’s 1-week prior to competition. Urine samples were collected at weigh-in, and hydration status was determined with urine specific gravity using a digital hand-held compact refractometer (P10S).
Main findings - Median dietary energy intake at baseline was 17170 (15598-26376) kJ. Macronutrient intake for carbohydrate (CHO), protein and fat were 411 (291-632) g, 194(134-216) g, and 209 (161-305) g, respectively. Dietary protein intake (expressed in g/kg body mass) was in-line with the recommendations for athletes, however median CHO intake at baseline [5.2 (3.2-11.7) g/kg] and 1-week prior to competition [3.1 (2.1-10.5) g/kg] was below the recommendations of 6-10g CHO/kg body mass for athletes performing one to three hours of moderate to high-intensity exercise. Fat intake (expressed in percentage) at baseline [44.0 (32.3-61.5)%] and 1-week prior to competition [40.9 (32.8-47.2)%] were above the recommended macronutrient distribution range (>35% of total energy), however athletes that do regular high-volume training may increase their fat intake up to 50% of total energy intake. Vitamin D intake at baseline [8(1-22) μg/d] and1-week prior to completion [5(0-9) μg/d] were both below the RDA of 15 μg/d. Calcium intake 1-week prior to competition [826 (522-1120) mg/d] was below the RDA of 1000mg/d. Magnesium at baseline [26 (21-334) mg/d] was below the RDA of 400 mg/d. The median body mass index (BMI) of the participants at baseline was classified as overweight (>24.9kg/m2), however, their median body fat percentage was low [7.6 (6.5-8.5) %]. All (100%) of the fighters reported the use of one or more weight-making practice to make weight before competition. Gradual weight loss was the most common weight-making practice reported in this study, with a prevalence of 88%, followed by hot baths (82%), water loading (71%), increasing exercise more than usual (59%) and training in rubber or plastic suits (59%). Seventy one percent (71%) of the MMA fighters restricted fluid intake in order to lose weight. Although body mass decreased significantly from baseline [80.4 (73.3-86.5) kg] to 1-week prior to weigh-in [76.9 (71.8- 81.2) kg], with an additional significant decrease to weigh-in 24-hours prior to competition [70.4 (66.8- 106.6) kg], body fat percentage did not change between baseline and pre-competition. At weigh-in 24-hours prior to competition, all of the participants that provided a voluntary urine sample were classified as moderately (57%) to severely (43%) dehydrated. Conclusion - The MMA fighters in the present study had a borderline high BMI but a healthy body fat percentage. Their dietary intake was in line with the macronutrient recommendations for athletes for protein, fat and the majority of micronutrients, however, CHO intake as well as vitamin D and calcium were below the recommended amounts. It is clear that MMA fighters in the present study are engaging in weight-making practices, particularly rapid weight loss practices that involve fluid loss and/or fluid restriction and that their influence on how to make weight mainly from their coaches and training colleagues, and not from a registered dietitian.. Although the MMA fighters lost a significant amount of weight from baseline to 1-week prior to weigh-in, they continued losing weight during the few days leading up to weigh-in 24-hours prior to competition. Based on the fact that all the MMA fighters who provided a urine sample at weigh-in were moderately to severely dehydrated, the weight lost during the few days prior to weigh-in was presumably water weight as a result of rapid weight loss practices. It should be recommended that the rule changes made by the California State Athletic Commission (CSAC) for Ultimate Fighting Championships (American based) that only allow a maximum of 8% weight difference between a week prior to weigh-in and weigh-in, should be implemented in Extreme Fighting Championships (in South Africa) as well to encourage fighters to enter realistic weight categories and limit the use of extreme weight making practices resulting in dehydration prior to weigh-in.Master
Complementary feeding knowledge and practices of health care personnel in Primary Health Care facilities in West Rand Health District
No full textMSc (Dietetics), North-West University, Potchefstroom CampusBackground: The United Nations Children’s fund (UNICEF) regard the complementary feeding period (6 – 24 months of age) as critical to ensure optimal child health, growth and development (UNICEF, 2019:2). Inadequate and inappropriate complementary feeding practices are identified as one of the key determinants of the high rates of stunting as well as overweight and obesity that is currently prevalent among infants and young children in South Africa (NDoH, Statistics SA, SAMRC & ICF, 2017:27). The provision of adequate and appropriate complementary feeding education and counselling by health care personnel to mothers/caregivers of infants and young children in Primary Health Care (PHC) facilities is considered to be one of the key strategies to improve complementary feeding practices at household level (Mushaphi et al., 2015:99). Even though there is limited recent studies on the knowledge and practices of health care personnel on complementary feeding practices, some resources have been able to identify selective provision of education and counselling on complementary feeding practices, and the communication of inaccurate and inconsistent complementary feeding messages to mothers/caregivers of infants and young children (Matlala, 2017:6). The aim of this study was to determine the knowledge and practices of health care personnel regarding the provision of adequate and appropriate complementary feeding education and counselling to mothers/caregivers of infants and young children in PHC facilities in West Rand Health District (WRHD). Objectives: The objectives of this study were to determine the knowledge of health care personnel with regard to adequate and appropriate complementary feeding practices as stipulated in the Road to Health Booklet (RtHB)/Side-by-Side booklet. Secondly, to assess the current practices of health care personnel in providing adequate and appropriate complementary feeding education and counselling to mothers/caregivers of infants and young children. The final objective was to compare the knowledge and practices of clinical and non-clinical health care personnel on the adequate and appropriate complementary feeding education and counselling provided to mothers/caregivers in line with the promotional messages in the RtHB/Side-by-Side booklet. Methods: This study was an observational study with a descriptive cross-sectional design that employed a quantitative approach to determine and assess the knowledge and practices of health care personnel with regard to complementary feeding education and counselling in PHC facilities in WRHD. The study population included health care personnel who regularly engage with mothers/caregivers of infants and young children aged 6 – 24 months (complementary feeding period) in 23 PHC facilities in WRHD. Health care personnel included in the study were professional nurses (PNs), enrolled nurses (ENs), enrolled nursing assistants (ENAs) (clinical health care personnel), and community health care workers (CHWs), lay counsellors, health promoters (HPs) and mentor mother counsellors (MMCs) (non-clinical health care personnel). Health care personnel excluded from the study were community district dietitians and medical practitioners. Participants were required to complete a pre-tested knowledge and practices questionnaire (Only available in English) that was developed based on the complementary feeding promotional messages in the RtHB/Side-by-Side booklet. Main findings: The total mean knowledge score on adequate and appropriate complementary feeding for health care personnel in the present study was only 44% (SD 18), despite the fact that the majority of them (77%; n=85) indicated that they have received some form of training on infant and young child feeding (IYCF). Clinical health care personnel achieved a higher knowledge score compared to non-clinical health care personnel [53 (46, 60)% vs. 33 (20, 47)%, p<0.001]. Knowledge regarding the correct age for the introduction of complementary foods, recognition that animal foods and mashed legumes are examples of appropriate complementary foods, identification of food sources rich in Vitamin C and food safety principles were good. However, knowledge regarding meal frequency, meal quantity, identification of food sources rich in Vitamin A, recommended drinks/milk in the complementary feeding period and responsive feeding practices was generally poor. Although the majority of health care personnel reported that they ‘routinely’ give complementary feeding advice (77%; n=86 ), complementary feeding education and counselling was mostly provided to pregnant women only (63%; n=70) and when baby is 6 months old (50%; n=56). Only 31% (n=34) of health care personnel reported that they utilise routine well-baby visits for the provision of complementary feeding education and counselling. The RtHB was the most common (67%; n=74) reported source of information on IYCF. Conclusion: Although health care personnel working in PHC facilities in WRHD do provide education and counselling regarding complementary feeding, mostly during pregnancy and when the infant is six months old, the overall mean knowledge score in this study was low. The non-clinical health care personnel achieved the lowest scores and areas of particular concern included meal frequency, meal quantity, recommended drinks/milk from 12 months of age, Vitamin A rich sources of complementary foods and responsive feeding practices. This study highlights the need to improve the knowledge and practices of health care personnel pertaining to adequate complementary feeding. Capacity can be built by providing regular refresher trainings on adequate and appropriate complementary feeding practices, with emphasis on meal frequency, meal quantity, recommended drinks/milk from 12 months of age, Vitamin A rich sources of complementary foods and responsive feeding practices. Furthermore, routine provision of complementary feeding education and counselling, not only to pregnant women but also to mothers/caregivers with infants and young children up to two years of age should be emphasised, and the particular barriers for not providing routine education should be identified and addressed.Master
Agreement between specific measures of adiposity and associations with high blood pressure in black South African women
No full textObjectives
To derive percentage body fat (%BF) cut-points according to body mass index (BMI) categories for adult black South African women and to investigate the agreement between adiposity classifications according to WHO BMI and %BF cut-points. The secondary aim was to determine the association between these different adiposity measures and high blood pressure.
Methods
Black women aged 29–65 years (n = 435) from Ikageng, South Africa, were included in this cross-sectional study. Socio-demographic and anthropometric data were collected (weight, height and BMI). %BF using dual-energy X-ray absorptiometry and blood pressure were measured.
Results
There was significant agreement between three %BF categories: low/normal (<35.8% age 29–49 years; or <38% age 50–65 years), overweight range (35.8–40.7% age 29–49 years; or 38–42.1% age 50–65 years) and obese (≥40.7% age 29–49 years; or ≥42.1% age 50–65 years) and three BMI categories: low/normal (<25 kg/m2), overweight range (25–29.9 kg/m2) and obese (≥30kg/m2); (κ = 0.62, P < .0001). Despite statistically significant agreement between groups, more than half of overweight individuals were misclassified as having either a normal (30.2%) or obese %BF (25.5%). %BF misclassification was low in the low/normal and obese BMI ranges. After adjustment for confounders, obesity (BMI ≥ 30kg/m2), as well as high %BF were significantly associated with high blood pressure (OR = 1.75, 95% CI 1.09–2.81 versus OR = 1.92, 95% CI 1.15–3.23, respectively).
Conclusion
Despite significant agreement between BMI and %BF categories, considerable misclassification occurred in the overweight range. Participants with excessive %BF had a greater odds of high blood pressure than those in the highest BMI categor
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