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Biomedical subjects

G T Ellison

Publications and source records attributed to G T Ellison.

At least 19 recordsLinked to original sources
PubMed2000

The reliability and validity of self-reported reproductive history and obstetric morbidity amongst Birth to Ten mothers in Soweto.

OBJECTIVE: To assess whether self-reports of reproductive history and obstetric morbidity provide an accurate basis for clinical decision-making. SETTING, PARTICIPANTS AND METHODS: Self-reports of maternal age and reproductive history, together with clinical measurements of five medical disorders, were abstracted from the obstetric notes of 517 mothers whose children were enrolled in the Birth to Ten study. These data were compared to self-reported information collected by interview during the Birth to Ten study. FINDINGS: The reliability of self-reported age and gravidity was high (R = 0.810-0.993), yet self-reports of previous miscarriages, terminations, premature- and stillbirths were only fairly reliable (Kappa = 0.48-0.50). Self-reported diabetes and high blood pressure had specificities of more than 95% for glycosuria, hypertension and pre-eclampsia. However, the specificity of self-reported oedema for hypertensive disorders and the specificity of self-reported urinary tract infection for STD seropositivity were only around 65%. CONCLUSIONS: The modest reliability and limited validity of self-reported obstetric morbidity undermines the clinical utility of this information. RECOMMENDATIONS: These results strengthen the case for providing mothers with "Home-based Maternal Records" to facilitate access to accurate obstetric information during subsequent clinical consultations.

Child↗
PubMed1999

Relative importance of heritable characteristics and lifestyle in the development of maternal obesity.

STUDY OBJECTIVE: To assess the relative importance of heritable characteristics and lifestyle in the development of "maternal obesity" after pregnancy. SETTING: South east London, in the homes of mothers who had delivered their babies at either Guy's, Lewisham or St Thomas's hospitals. PARTICIPANTS: Seventy four mothers of low antenatal risk who had been enrolled in the Antenatal Care (ANC) Project (a previous trial of antenatal care) during the first trimester of pregnancy, and who had subsequently been followed up 2.5 years after delivery. DESIGN: Information on parental obesity, psychosocial and sociodemographic factors as well as lifestyle, was gathered during a semi-structured interview at each mother's home. Additional anthropometric and psychosocial data were taken from the existing ANC Project database. These data were used to assess the relative importance of heritable characteristics and lifestyle on changes in maternal body weight from the beginning of pregnancy to the follow up interview. MAIN RESULTS: After adjusting for the effects of potential confounders and known risk factors for maternal obesity, women who selected larger silhouettes to represent their biological mothers were significantly more likely to have higher long term weight gains than those who selected thinner maternal silhouettes (r = 0.083, p = 0.004). Women who were less satisfied with their bodies postpartum had significantly greater long term weight gains than those women who displayed no increase in dissatisfaction with their bodies after pregnancy (r = 0.067, p = 0.010). CONCLUSIONS: A heritable predisposition to gain weight together with changing attitudes to body size, both had an independent role in the development of maternal body weight after pregnancy. Differences in each woman's heritable predisposition to gain weight and any changes in body image that occur after pregnancy might explain why some women gain weight in association with pregnancy.

Adult↗
PubMed1999

An inverse relation between blood pressure and birth weight among 5 year old children from Soweto, South Africa.

STUDY OBJECTIVE: To examine the relation between birth weight and blood pressure at 5 years in a cohort of South African children. DESIGN: Prospective cohort study. PARTICIPANTS: 849 five year old children. SETTING: Soweto, a sprawling urban area close to Johannesburg, South Africa, which was a designated residential area for people classified as "black" under apartheid legislation. MAIN RESULTS: Systolic blood pressure at 5 years was inversely related to birthweight (r = -0.05, p = 0.0007), independent of current weight, height, gestational age, maternal age or socioeconomic status at 5 years. There was no relation between birth weight and diastolic blood pressure. After adjusting for current weight and height, there was a mean decline in systolic blood pressure of 3.4 mm Hg (95% confidence intervals 1.4, 5.3 mm Hg) for every 1000 g increase in birth weight. CONCLUSIONS: These data from a disadvantaged urbanised community in Southern Africa extend the reported observations of an inverse relation between birth weight and systolic blood pressure. The study adds to the evidence that influences in fetal life and early childhood influence systolic blood pressure. Further research is required to assess whether efforts to reduce the incidence of low birthweight babies will attenuate the prevalence of hypertension in future generations.

Birth Weight↗
PubMed1999

Do the psychosocial and behavioral changes that accompany motherhood influence the impact of pregnancy on long-term weight gain?

The aim of the present study was to assess whether the psychosocial and behavioral changes that occur during and after pregnancy influence long-term weight gain. The study examined 74 mothers enrolled in the Antenatal Care (ANC) Project (a randomized controlled trial of antenatal care based in South London), all of whom had volunteered to take part in a subsequent follow-up study. Data on body weight at the beginning of pregnancy; lifestyle and behavior during pregnancy; antenatal care and obstetric history; together with measures of postnatal depression and parenting stress following pregnancy were taken from the existing ANC Project database. Additional measurements of height and weight together with information on a variety of lifestyle changes and psychosocial characteristics, were gathered during semi-structured interviews at each mother's home, two and a half years after their children had been born. The results show that pregnancy-related weight gains are not simply the result of retaining weight that is gained during pregnancy, but that they also originate from gaining additional weight in the postpartum period. Mothers who felt they ate more after their children were born, had significantly greater long-term weight gains (2.78 (1.42) kg) than those who felt that they had not increased their food intake (-1.15 (0.76) kg; t = 2.49, p = 0.016). Similarly, mothers who felt they had greater access to food postpartum, had significantly greater long-term weight gains (1.70 (0.87) kg) than those who felt they did not have greater access to food (-1.37 (1.13) kg; t = 2.18, p = 0.032). There was some evidence that the lifestyle changes which accompany pregnancy and motherhood increase some women's vulnerability to eating disorder psychopathology. Mothers who felt they did less exercise after pregnancy than they did before, were also at greater risk of long-term weight gain (p = 0.028), as were mothers with low numbers of supportive individuals (p = 0.033). Neither the stress of parenting nor maternal depression were significantly associated with an increased risk of long-term weight gain (p > 0.05).

Adult↗
PubMed1998

How accurate are antenatal weight measurements? A survey of hospital and community clinics in a South Thames Region NHS Trust.

The accuracy of antenatal weight data recorded in obstetric notes was investigated in the 45 hospital and community antenatal clinics within a South Thames Region NHS Trust. In order to assess the reliability and validity of all 60 clinic scales triplicate measurements of body weight for low- and high-weight subjects were recorded on each clinical scale and on a calibrated standard scale. The quality of weighing practice during antenatal care was investigated by means of semi-structured interviews conducted with all 33 midwives who currently provide antenatal care within the Trust. Beam balances had the highest reliability and validity, whereas scales with spring mechanisms were the least accurate. Only 40% of the clinics surveyed had access to beam balances, yet most of the maternal weight measurements recorded during antenatal care are likely to be out by no more than 1-1.5% of body weight. Weighing practice was generally inconsistent, and serial measurements of maternal body weight collected during pregnancy are probably too imprecise to provide a sensitive screen for conditions associated with unusual weight gain and too inaccurate to assess compliance with guidelines for weight gain.

Body Weight↗
PubMed1998

Are overweight women at increased risk of obesity following pregnancy?

Longitudinal studies suggest that women who already have a high BMI are at greater risk of maternal obesity than their lighter counterparts. The aim of the present study was to investigate this possibility by examining the relationship between reproductive history and maternal BMI in a community of 627 women from South Africa with a high prevalence of obesity. Standardized questionnaires were used to obtain detailed sociodemographic and behavioural information, while maternal weight and height were both measured at the time of the interview. Analysis of covariance (ANCOVA) showed that maternal age (r2 0.015, P = 0.001), smoking status (r2 0.012, P = 0.036), and social support (r2 0.011, P = 0.006) were all independently associated with maternal BMI. If overweight women were at increased risk of maternal obesity, then the positive relationship between reproductive history and maternal BMI should be enhanced in this relatively obese community, yet the ANCOVA models showed no independent association between gravidity and maternal BMI after controlling for the effects of confounding factors. Although previous longitudinal studies have found a positive association between prepregnant weight and long-term weight gain, this relationship might arise because overweight women gain more weight over a fixed period of time than normal weight women, and therefore they may appear to be at greater risk of pregnancy-related weight gains. Overweight women are at greater risk of weight gain generally, but there is little unequivocal evidence to suggest that they are at any increased risk of maternal obesity, when compared with women of lower BMI.

Adult↗
PubMed1997

The impact of pregnancy on the long-term weight gain of primiparous women in England.

OBJECTIVES: To investigate the impact of pregnancy on long-term weight gain of primiparous mothers in England, and to identify potential risk factors for maternal obesity. DESIGN: A retrospective, repeat-pregnancy study which examined the change in maternal body weight from the beginning of the first successful pregnancy to the beginning of the second. SUBJECTS: Two hundred and forty-three mothers, all of whom had been weighed during the first trimester of their first and second pregnancies, and none of whom had fallen pregnant less than 12 months after the birth of their first child. MEASUREMENTS: Sociodemographic, behavioural, medical, obstetric and perinatal data, together with antenatal measurements of maternal body weight and height, were extracted from each mother's obstetric notes. A comprehensive survey of weighing scales used at all antenatal clinics was undertaken. RESULTS: After accounting for the effect of ageing, there was no significant long-term increase in mean maternal body weight following the first pregnancy (95% Confidence Intervals: -0.82-0.28kg). While most mothers (70.8%) gained 1.0 kg or less, 24.7% gained more than 1.54 kg. Even after accounting for the maximum error in clinic scales, 14.8% of the mothers gained 1.54 kg or more in association with their first pregnancy. Mothers with higher BMIs at the beginning of their first pregnancy, who gained more weight during pregnancy, gave birth to heavier babies and had longer intervals between their pregnancies, gained significantly more weight from one pregnancy to the next. CONCLUSIONS: Pregnancy has little impact on the mean weight gain of primiparous women from England, who have a low prevalence of obesity (BMI > or = 26.0, 25.5%). Nevertheless, pregnancy may be associated with a permanent increase in maternal body weight simply because it is a period of positive energy balance during which some women gain excessive weight. Other factors, such as prepregnant BMI, determine whether long-term weight gain actually occurs.

Adult↗
PubMed1997

The use of maternal weight measurements during antenatal care. A national survey of midwifery practice throughout the United Kingdom.

The aim of the present study was to examine the use of maternal weight measurements during antenatal care throughout the United Kingdom. A postal questionnaire and follow-up letter were sent to 1500 midwives throughout the United Kingdom, selected at random from the UKCC register. The postal survey achieved a response rate of 44.8% (672/1500 questionnaires), and obtained responses from at least 10 midwives in all but the lowest grade. Respondents were representative of midwives practising throughout the country, in terms of their gender, working hours and grade, although there were fewer midwives in community settings than those in a contemporary representative English sample. The questionnaire obtained information on the background, training and experience of each midwife, together with their attitudes towards antenatal weighing. For those midwives currently involved in antenatal care, additional information was collected on the schedule of antenatal weight measurements, the criteria used to identify 'abnormal' weight gain, and the action taken in response to 'abnormal' weight gain. 61.8% of the midwives thought that the pattern of maternal weight gain was 'not important' in antenatal care, and only 51.5% of those who currently provided antenatal care weighted women at every antenatal visit. However, most midwives (86.1%) cited at least one clinical condition to explain why women are routinely weighed during pregnancy, and over a third of midwives thought that maternal weight gain could detect seven clinical conditions, including obesity, oedema, pre-eclampsia and polyhydramnios. Midwives with more advanced qualifications (degrees and teaching qualifications) and those working in educational or community settings were least likely to believe that weight gain was good at detecting clinical outcomes. Differences in the perceived utility of antenatal weighing influenced whether midwives would act in response to 'abnormal' maternal weight gain, and whether they advised women to gain or lose weight during pregnancy. However, the criteria that midwives used for identifying 'abnormal' weight gain were variable, and often inappropriate, so that different midwives are unlikely to intervene consistently or to give consistent advice on the basis of maternal weight gain. These differences in practice may lead to extensive and inappropriate variation in antenatal care. Clear guidelines are urgently required to ensure that, if maternal weight measurements are collected during antenatal care, they are collected and used consistently.

Adult↗
PubMed1997

The reliability of hand-written and computerised records of birth data collected at Baragwanath hospital in Soweto.

This study examined the reliability of hand written and computerised records of birth data collected during the Birth to Ten study at Baragwanath Hospital in Soweto. The reliability of record-keeping in hand-written obstetric and neonatal files was assessed by comparing duplicate records of six different variables abstracted from six different sections in these files. The reliability of computerised record keeping was assessed by comparing the original hand-written record of each variable with records contained in the hospital's computerised database. These data sets displayed similar levels of reliability which suggests that similar errors occurred when data were transcribed from one section of the files to the next, and from these files to the computerised database. In both sets of records reliability was highest for the categorical variable infant sex, and for those continuous variables (such as maternal age and gravidity) recorded with unambiguous units. Reliability was lower for continuous variables that could be recorded with different levels of precision (such as birth weight), those that were occasionally measured more than once, and those that could be measured using more than one measurement technique (such as gestational age). Reducing the number of times records are transcribed, categorising continuous variables, and standardising the techniques used for measuring and recording variables would improve the reliability of both hand-written and computerised data sets.

Data Collection↗
PubMed1997

Methodological considerations in the design of an obstetric database abstracted from medical records.

The quality of maternal information contained within contemporary obstetric notes was investigated by abstracting data from the medical records of multiparous women who were admitted to a major city hospital in the South Thames Region. Potential sources of error were identified by comparing information recorded in different sections of each obstetric notes and within the obstetric notes of consecutive pregnancies. The format of the obstetric notes largely determined which variables were recorded and, to some extent, the accuracy of information collected. However, the quality of the data ultimately depended upon whether each variable was self-reported or directly measured. Self-reported variables were subject to selective omission and subjective bias, while measured variables were susceptible to inaccurate equipment and poor measurement practice. By interviewing a sample of midwives currently involved in antenatal care at the Trust it was possible to confirm that extensive variation in measurement and recording procedures routinely occurred.

England↗
PubMed1997

The use of 'racial' categories in contemporary South African health research. A survey of articles published in the South African Medical Journal between 1992 and 1996.

OBJECTIVE: In the light of growing concern about the clinical, social and political impact of 'racial' categorisation in health research, this survey aimed to re-evaluate the current use of 'racial' categories in articles published by the South African Medical Journal. SURVEY DESIGN: Any categories that might have been used or interpreted as measures of genetically determined 'racial' differences (including 'racial', ethnic and sociopolitical 'population group' categories) were included in this survey of 668 articles describing South African health research published during the past 5 years. By classifying the research contained in each of these articles it was possible to assess the importance of 'racial' categorisation in study design. The explanations given for any 'racial' differences in health were then used to evaluate the impact of 'racial' categorisation on the perception that innate characteristics were responsible. RESULTS: Three hundred and seventeen (47.5%) articles mentioned one or more 'racial' categories, 292 (43.7%) of which used 'racial' categories to describe the subjects they studied. The commonest generic labels used for these categories were "race" and "population group", while the commonest descriptive labels referred to traditional 'racial' characteristics such as phenotype, nationality and geographical origin. Only 15 (5.1%) articles fully defined the categories and labels they used, and many more used different generic and descriptive labels interchangeably. The use of 'racial' categories was highest among genetic (73.9%), descriptive (55.3%) and quasi-experimental studies (38.2%), although most used these categories simply to describe the subjects they examined. Of those 162 (24.3%) articles that discussed 'racial' differences in health, only 120 (18.0%) contained an explanation, and 60 of these suggested that inherent genetic or behavioural factors were responsible. Nine articles contained derogatory statements that could be interpreted as prejudiced or racist. CONCLUSION: The use of 'racial' categorisation remains widespread in South African health research. By using generic and descriptive labels from traditional 'racial' taxonomies, many of these articles reinforce the perception that distinct human 'races' exist. Although most of the articles failed to explain any of the 'racial' differences in health they observed, it is likely that these will be interpreted as evidence of innate genetic or behavioural differences, like those suggested by the few articles that offered explanations. The continued use of 'racial' categorisation in health research might be inevitable, particularly for examining the impact of social forces, such as apartheid and other forms of racism, that use 'racial' categories to create unequal access to health and health care. However, any studies that use 'racial' categories should be careful to avoid legitimising the biological concept of 'race', misidentifying the causes of 'racial' disparities in health and reinforcing 'racial' prejudice.

Bias↗
PubMed1996

Why do pouched mice (Saccostomus campestris) hoard food?

The function of food hoarding in Saccostomus campestris was investigated by examining the effect of photoperiod and temperature on the amount of two different types of food that were eaten and stored in artificial burrows by pouched mice from four different localities which experience contrasting climatic regimes. Food consumption was influenced by a variety of factors including the type of food, the sex of the individual, photoperiodic and temperature conditions, and the locality from which the animals originated. Females did not hoard significantly more food than males, which might have indicated that the solitary females hoard additional food specifically to provision their young. There was also no evidence that pouched mice hoard food to prepare for future periods of food scarcity, because there was no significant effect of photoperiod or temperature on hoarding activity, and the geographical variation in hoarding observed was not related to differences in climatic conditions at the different localities. However, geographical differences in food consumption and food hoarding were similar so that populations which ate the most food also hoarded the most food. Likewise, hoarding was selective and directed towards preferred food items. It therefore appears that food hoarding in this species may simply be a component of feeding behaviour and possibly serves to limit the amount of time spent processing food outside the burrow.

Animals↗