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Biomedical subjects

Rebecca Hardy

Publications and source records attributed to Rebecca Hardy.

At least 19 recordsLinked to original sources
PubMed2006

Postnatal depression and the original mother-child relationship: a prospective cohort study.

BACKGROUND: Previous studies assessing the role of early mother-child relationship as a risk factor for postnatal depression have been cross-sectional and/or retrospective in nature. AIMS: To examine associations between early mother-child relationship (assessed prospectively and retrospectively) and later risk of postnatal depression. METHODS: Dataset from national 1946 birth cohort study; 1137 women at age 51, completed a modified version of the Bromley Postnatal Depression Scale. RESULTS: Compared with women who did not experience maternal separation or recalled moderate to best level of care, women who experienced maternal separation for 3.5 days or more in early childhood and who felt they received a low level of maternal care were at higher risk of postnatal depression (odds ratio (95% CI): 2.4 (1.51-3.79), p=0.001); this relationship was robust to adjustment for current psychological status. Regular enuresis at age of 6 years (2.2 (1.01-4.90), p=0.05), and lack of emotional closeness in current maternal relationship (1.6 (1.01-2.46), p=0.04) were also associated with increased postnatal depression risk. Insufficient evidence was found for a link between other indicators of early behaviour and temperament (anxious, antisocial, or neurotic behaviour) and reported postnatal depression. LIMITATIONS: Postnatal depression was assessed retrospectively using self-report, introducing potential bias in recall. CONCLUSION: Women who experienced early maternal separation and recalled the lowest level of maternal care had a particularly high risk of postnatal depression. In the treatment and management of postnatal depression, the results support health professionals in their consideration of the woman's past and current relationship with her mother; both actual events and the woman's perceptions of them.

Cohort Studies↗
PubMed2006

Social circumstances and education: life course origins of social inequalities in metabolic risk in a prospective national birth cohort.

OBJECTIVES: We investigated the relative importance of education and childhood and adult social class in the risk of metabolic syndrome. METHODS: We conducted a prospective birth cohort study of 1311 men and 1318 women aged 53 years in 1999, when metabolic syndrome components were measured. Logistic regression analyses were used to calculate relative index of inequality estimates. RESULTS: Relative to men and women at the highest education levels, men (odds ratio [OR]=2.0; 95% confidence interval [CI]=1.2, 3.2) and women (OR=2.7; 95% CI=1.5, 4.6) with the least education were at twice the risk or more of having the metabolic syndrome. Adjustment for childhood and adult social class strengthened this result among men and weakened it among women. Childhood social class was independently associated with the metabolic syndrome in women (OR=2.0; 95% CI=1.1, 3.6) but not in men (OR=1.1; 95% CI= 0.7, 1.8). Associations between adult social class and the metabolic syndrome or its components were largely accounted for by childhood socioeconomic measures. CONCLUSIONS: Educational differences should be considered in the design of interventions aimed at reducing the burden of the metabolic syndrome in socially disadvantaged groups.

Child, Preschool↗
PubMed2006

Neighborhood social capital and dental injuries in Brazilian adolescents.

OBJECTIVES: Evidence suggests that communities with higher levels of social capital have better health, but this association has not been explored specifically in relation to dental injury. We investigated the association between social capital and dental injury. METHODS: We conducted a multilevel study assessed individual and neighborhood effects on dental injury of 1302 14- to 15-year-old adolescents in 39 schools of Distrito Federal, Brazil. Children underwent a dental examination and, with their parents, answered a questionnaire about their local environments. Our data analysis used logistic multilevel modeling of students and neighborhood (the latter defined by catchment areas of schools). RESULTS: The prevalence of dental injury was significantly lower in neighborhoods with higher levels of social capital, especially among boys. After control for individual and neighborhood variables, the adjusted odds ratio for a 1-unit increase in the standardized social capital index was 0.55 (95% confidence interval=0.37, 0.81; P=.002) among boys. CONCLUSIONS: Social capital may explain inequalities in rates of dental injury, especially among boys.

Adolescent↗
PubMed2006

Developmental origins of midlife physical performance: evidence from a British birth cohort.

The authors hypothesized that 1) physical growth, as a marker of the early development of muscle fibers, and 2) advanced childhood motor and cognitive abilities, as markers of central nervous system development, would be positively related to midlife standing balance and chair rising, independently of later life experiences. They tested these hypotheses in a representative British sample of 1,374 men and 1,410 women aged 53 years in 1999 with prospective childhood measures of heights and weights, age at first standing and walking, cognitive ability, and motor coordination. Weight gain before age 7 years was positively related to adult performance in men but not women, independently of later body size, social class, physical activity, and health status. Attainment of motor milestones at the modal age and higher scores on tests of cognitive ability and motor coordination were associated with better performance, independently of other factors. This study is the first to show that childhood growth and development affect midlife performance; prevention of disability and frailty in later life may need to start early.

Adolescent↗
PubMed2006

Cessation of hormone replacement therapy after reports of adverse findings from randomized controlled trials: evidence from a British Birth Cohort.

OBJECTIVES: We examined the cessation of hormone replacement therapy (HRT) among British women, by educational level, social class, and cardiovascular risk factors, at the time of publicity about 2 clinical trials of HRT that were halted after adverse findings. METHODS: A total of 1387 women aged 57 years reported their monthly HRT use between January 2002 and February 2003. A succession of regression-based time-series models were fitted to detect changes in the proportion of HRT users stratified by education level, social class, hypertension, and obesity. RESULTS: The overall percentage of HRT users declined from 31% in January 2002 to less than 26% by February 2003. Changes in trends of HRT use were first detected in June 2002 (for women with advanced secondary educational qualification or higher) and in July 2002 (for all other groups). The rate of decline was greatest for women with no formal educational qualifications, from the manual social class, or who were hypertensive or obese. CONCLUSIONS: These decreases coincided with the announced cessation of a large US clinical trial of HRT. This publicity may have had a differential influence on the immediate decline in HRT use by various groups of British women.

Educational Status↗
PubMed2006

Developmental origins of midlife grip strength: findings from a birth cohort study.

BACKGROUND: There is growing evidence that the prenatal environment has long-term effects on adult grip strength, but little is known about the effects of the postnatal environment. We tested whether prepubertal growth, pubertal growth, or the development of motor and cognitive capabilities was associated with midlife muscle strength independently of other determinants of grip strength. METHODS: Handgrip strength and body size were measured in a representative British sample of 1406 men and 1444 women 53 years old with prospective childhood data. Normal regression models were used to examine the effects of birth weight, postnatal height and weight gain before 7 years and between 7 and 15 years, motor milestones and cognitive ability on grip strength at age 53, taking account of lifetime social class, current physical activity, and health status. RESULTS: Birth weight and prepubertal height gain were associated with midlife grip strength, independently of later weight and height gain and other determinants. Pubertal growth was also independently associated with midlife grip strength; for men weight gain during puberty was beneficial, whereas for women it was height gain. Those participants with earlier infant motor development had better midlife grip strength, which was partly confounded by the growth trajectory. CONCLUSIONS: This study showed that components of prenatal, prepubertal, and pubertal growth have long-term effects on midlife grip strength. To the extent that these associations are modifiable, interventions in childhood that help to build muscle mass and strength, such as increased physical exercise, may have long-term beneficial effects on adult muscle strength and may help to prevent sarcopenia, disability, and frailty in later life.

Adolescent↗
PubMed2006

Age at puberty and adult blood pressure and body size in a British birth cohort study.

OBJECTIVE: To investigate the association between age at puberty and blood pressure at age 53 years. DESIGN: A prospective birth cohort study with regular contacts through childhood and adulthood until the age of 53 years. PARTICIPANTS: A total of 1193 men and 1204 women, from a sample of 5362 born in Britain in March 1946. MAIN OUTCOME MEASURE: Blood pressure at age 53 years. RESULTS: Regression models indicated that men who had reached puberty latest had a lower mean systolic blood pressure (SBP; P = 0.03) and diastolic blood pressure (DBP; P = 0.01) at 53 years than others. The mean SBP (95% confidence interval) was 6.4 mmHg (1.8, 10.9) greater in the earliest puberty group compared with the latest; for DBP the difference was 4.6 mmHg (1.9, 7.4). The associations were not accounted for by current body size, even though later puberty was associated with a decreasing body mass index (BMI) at 53 years. Neither were they accounted for by prepubertal body size, birth weight, or childhood and adult social class. Although women who reached puberty early had a higher BMI and shorter stature at 53 years compared with other women, they did not have higher blood pressure. CONCLUSIONS: Better health behaviours in men reaching puberty late may explain the association between age at puberty and blood pressure. Alternatively, age at puberty may be a marker of the whole growth trajectory, distinguishing characteristics important in the later development of high blood pressure. The association of early puberty with high adult BMI in both sexes highlights the importance of controlling obesity in those who mature early.

Aging↗
PubMed2006

The potential impact of neighborhood empowerment on dental caries among adolescents.

OBJECTIVE: Empowerment has been considered a dimension of social capital. It refers to social interaction processes that enable people to enhance their individual and collective skills and to exert greater control over their lives. This relationship has not been explored in relation to dental health. The objective of this study was to investigate the association between neighborhood empowerment and dental caries in adolescents. METHODS: A multilevel study was designed to assess the individual and neighborhood effects on the oral health of adolescents. Four sources of data were used: (a) clinical examinations (WHO), (b) students' questionnaires, (c) parents' questionnaires and (d) census data. The study population was 1302, 14/15-year-old students from 39 public schools of two cities of the Distrito Federal (DF), Brazil. Data analysis used logistic multilevel modeling at two levels: students (sources a and b) and neighborhood as defined by catchment areas of schools (sources c and d). RESULTS: High DMFT (DMFT > median, DMFT > or =3) rates were significantly lower in areas with higher levels of empowerment. This relationship was independent of socioeconomic variables at the individual and area levels and of all other individual risk factor variables such as sex, fluoride, sugar consumption, tooth brushing and dental attendance [OR for low compared with high empowerment was 1.54 (95% CI = 1.09-2.18), P = 0.014]. CONCLUSIONS: Neighborhood empowerment may play an important role in explaining inequalities in the levels of dental caries. New perspectives are needed so that more effective interventions can be implemented using area-based perspectives.

Adolescent↗
PubMed2006

Life course social roles and women's health in mid-life: causation or selection?

STUDY OBJECTIVE: To investigate whether relations between social roles and health are explained by health selection into employment and parenthood by examining the influence of early health on relations between long term social role histories and health in mid-life. DESIGN: Prospective, population based, birth cohort study. PARTICIPANTS AND SETTING: Women from a national British cohort born in 1946, including 1171 women with a valid measure of self reported health at age 54 and valid work and family role measures at ages 26, 36, 43, and 53, as well as 1433 women with a valid body mass index (BMI) measure at age 53 and valid work and family role measures at ages 26, 36, 43, and 53. OUTCOME MEASURES: Self reported health at age 54 and obesity at age 53, taken from objective height and weight measures conducted by a survey nurse during face to face interviews in respondents' homes. MAIN RESULTS: Women who occupied multiple roles over the long term reported relatively good health at age 54 and this was not explained by early health. Women with weak long term ties to the labour market were more likely to be obese at age 53. Examination of body mass index (BMI) from age 15 showed that long term homemakers were larger than other women from age 26, but their mean BMI increased significantly more with age than that of other women. CONCLUSIONS: Relations between social roles and health were generally not explained by health selection into employment and parenthood, although some health selection may occur for obesity.

Adult↗
PubMed2005

Statistical issues in life course epidemiology.

There is growing recognition that the risk of many diseases in later life, such as type 2 diabetes or breast cancer, is affected by adult as well as early-life variables, including those operating prior to conception and during the prenatal period. Most of these risk factors are correlated because of common biologic and/or social pathways, while some are intrinsically ordered over time. The study of how they jointly influence later ("distal") disease outcomes is referred to as life course epidemiology. This area of research raises several issues relevant to the current debate on causal inference in epidemiology. The authors give a brief overview of the main analytical and practical problems and consider a range of modeling approaches, their differences determined by the degree with which associations present (or presumed) among the correlated explanatory variables are explicitly acknowledged. Standard multiple regression (i.e., conditional) models are compared with joint models where more than one outcome is specified. Issues arising from measurement error and missing data are addressed. Examples from two cohorts in the United Kingdom are used to illustrate alternative modeling strategies. The authors conclude that more than one analytical approach should be adopted to gain more insight into the underlying mechanisms.

Causality↗
PubMed2005

A new ENU-induced allele of mouse quaking causes severe CNS dysmyelination.

The mutant allelic series of the mouse quaking gene consists of the spontaneous quaking(viable) (qk(v)) allele, which is homozygous viable with a dysmyelination phenotype, and four ENU-induced alleles (qk(kt 1), qk(k2), qk(kt3/4), and qk(l-1)), which are homozygous embryonic lethal. Here we report the isolation of qk(e5), the first ENU-induced viable allele of quaking. Unlike qk(v)/qk(v), qk(e5)/qk(e5) animals have early-onset seizures, severe ataxia, and a dramatically reduced lifespan. Ultrastructural analysis of qk(e5)/qk(e5) brains reveals severe dysmyelination when compared with both wild-type and qk(v)/qk(v) brains. In addition, Calbindin detection in young adult qk(e5)/qk(e5) mice reveals Purkinje cell axonal swellings indicative of neurodegeneration , which is not seen in young adult qk(v)/qk(v) mice. Although the molecular defect in the qk(e5) allele is not evident by sequencing, protein expression studies show that qk(e5)/qk(e5) postnatal oligodendrocytes lack the QKI-6 and QKI-7 isoforms and have reduced QKI-5 levels. The oligodendrocyte developmental markers PDGF alpha R, NG 2, O4, CNP, and MBP are also present in the qk(e5)/qk(e5) postnatal brain although CNP and MBP levels are considerably reduced. Because the qk(v) allele is a large deletion that affects the expression of three genes, the new neurologic qk(e5) allele is an important addition to this allelic series.

Alleles↗
PubMed2005

Birthweight and blood pressure in five European birth cohort studies: an investigation of confounding factors.

BACKGROUND: It has been suggested that the association between birthweight and blood pressure has been overstated as a result of publication bias and, within studies, a lack of adjustment for potentially important maternal and socioeconomic confounding factors and 'overadjustment' for current body size. This study investigates the impact of potential confounding variables on the birthweight-blood pressure association in birth cohort studies from different time periods and geographical locations in Europe. METHODS: Data from five European birth cohort studies (from Finland, the UK, and the Faroe Islands) taking part in the European Birth-Lifecourse-Studies (EURO-BLCS) project were analysed. Birthweight was measured at birth in all cohorts and confounding variable information was collected prospectively at subsequent follow-ups in all cohorts. Regression models were used to assess the unadjusted association between birthweight and blood pressure and then to assess the impact of potential maternal and socioeconomic confounding variables and adjustment for later body size. Analyses were carried out in the same way across all five cohorts. RESULTS: Birthweight was consistently negatively associated with systolic blood pressure (SBP) across all cohorts. Gestational age and possibly maternal pre-pregnancy weight, but not socioeconomic status, may be important confounding factors of the relationship between birthweight and SBP. The size of the birthweight-SBP association in adulthood may be larger than in childhood before adjustment for current body size, although a cohort effect cannot be ruled out. CONCLUSION: This study highlights the value of future cross-cohort comparisons in the investigation of the foetal origins of adult disease.

Adolescent↗
PubMed2005

Childhood cognitive ability and age at menopause: evidence from two cohort studies.

OBJECTIVE: To investigate whether poorer cognitive ability in childhood is associated with an earlier menopause. DESIGN: Two cohorts were included: a nationally representative British birth cohort study of 1,350 women born in March 1946 and followed up to age 54 years, and an Aberdeen cohort study of 3,465 women born in Aberdeen from 1950 to 1956 and followed up to age 44 to 50 years. Both cohorts had prospective information on childhood cognitive ability at age 7 or 8 years. RESULTS: In both cohorts, women with lower cognitive scores in childhood reached menopause earlier than women with higher scores. With follow-up of menopause to 49 years, the hazard ratio (HR) for one standard deviation of the cognitive score was 0.80 (95% CI, 0.72-0.90) in the Aberdeen cohort and 0.84 (95% CI, 0.73-0.97) in the older 1946 birth cohort. The effect was still evident in the 1946 birth cohort with follow-up of menopause to 53 years (HR = 0.87; 95% CI, 0.79-0.95). These ratios were weakly attenuated by adjustment for potential confounding effects of lifetime socioeconomic circumstances, parity, and smoking. CONCLUSIONS: The association between early cognitive ability and timing of menopause only partially reflects common risk factors, although residual confounding remains a possibility. Alternatively, early environmental or genetic programming may explain this association, perhaps through setting lifelong patterns of hormone release or causing transient hormonal changes at sensitive periods of development. These findings have implications for the interpretation of studies investigating an association between age at menopause and adult cognitive function.

Adult↗
PubMed2005

Influence of short stature on the change in pulse pressure, systolic and diastolic blood pressure from age 36 to 53 years: an analysis using multilevel models.

BACKGROUND: Previous cross-sectional analyses of this cohort have shown that short height and leg length are associated with higher pulse pressure and systolic blood pressure in middle age. It is unclear how these adult measures of childhood growth influence the change in blood pressure as it increases with age. METHODS: Multilevel models were fitted to investigate associations between components of height and the change in blood pressure between 36, 43, and 53 years in a prospective national cohort of 1472 men and 1563 women followed-up since birth in 1946. RESULTS: Shorter height and leg length, but not trunk length, were associated with higher blood pressure, similarly in men and women. Longitudinal analyses showed that the effects of both height and leg length on pulse pressure and systolic blood pressure became significantly stronger with age. For example, the change in systolic blood pressure was found to be -0.021 mm Hg (95% confidence interval -0.029 to -0.013) per year lower for every centimetre increase in leg length (P < or = 0.001). In other words, the increase in systolic blood pressure over a 10 year period of a participant whose legs were 10 centimetres shorter was 2.1 mm Hg higher (P < or = 0.001), compared with a taller participant. Associations were independent of a number of potential confounders. CONCLUSIONS: These results support the hypothesis that short people may be more susceptible to the effects of ageing on the arterial tree. Childhood growth may contribute to the tracking of cardiovascular risk throughout life.

Adult↗
PubMed2005

Grip strength, postural control, and functional leg power in a representative cohort of British men and women: associations with physical activity, health status, and socioeconomic conditions.

BACKGROUND: Understanding the health, behavioral, and social factors that influence physical performance in midlife may provide clues to the origins of frailty in old age and the future health of elderly populations. The authors evaluated muscle strength, postural control, and chair rise performance in a large representative prospective cohort of 53-year-old British men and women in relation to functional limitations, body size, health and activity, and socioeconomic conditions. METHODS: Nurses interviewed 2984 men and women in their own homes in England, Scotland, and Wales and conducted physical examinations in 2956 of them. Objective measures were height, weight, and three physical performance tests: handgrip strength, one-legged standing balance time, and time to complete 10 chair rises. Functional limitations (difficulties walking, stair climbing, gripping, and falls), health status, physical activity, and social class were obtained using a structured questionnaire. RESULTS: Those with the worst scores on the physical performance tests had higher rates of functional limitations for both upper and lower limbs. Women had much weaker handgrip strength, somewhat poorer balance time, and only slightly poorer chair rise time compared with men. In women, health problems and low levels of physical activity contributed to poor physical performance on all three measures. In men, physical activity was the predominant influence. Heavier weight and poorer socioeconomic conditions contributed to poorer balance and chair rise times. CONCLUSIONS: In this representative middle-aged group, physical performance levels varied widely, and women were seriously disadvantaged compared with men. In general, physical performance was worse for men and women living in poorer socioeconomic conditions with greater body weight, poorer health status, and inactive lifestyles. These findings support recommendations for controlling excess body weight, effective health interventions, and the maintenance of active lifestyles during aging.

Cohort Studies↗
PubMed2005

Social and environmental conditions across the life course and age at menopause in a British birth cohort study.

OBJECTIVE: To assess whether socio-economic status, environmental stress and hardship throughout the life course are associated with age at menopause. DESIGN: Birth cohort study. SETTING: England, Scotland, Wales. SAMPLE: A total of 1515 women from a stratified sample of all births in one week in 1946. METHODS: Age at menopause was collected using annual postal questionnaires from age 47 to 53 years. Information on socio-economic conditions and hardship were collected at contacts throughout life from age 2 to 43 years. Socio-economic indicator variables were defined to represent cumulative exposure to hardship in childhood and in adulthood. MAIN OUTCOME MEASURES: Age at menopause. RESULTS: Cox's proportional hazard models indicated that women whose fathers were in a manual social class occupation at three time points during her childhood had an earlier age at menopause than those whose fathers were in non-manual occupations at all three (HR: 1.51; 95% CI: 0.93-2.47). Similar findings were seen for household crowding. These socio-economic gradients could not be explained by adult socio-economic status, behaviour and lifestyle or by psychological health and stress, but were attenuated by other early life factors. Women who experienced parental divorce early in life (before five years of age) had double the rate of menopause of those whose parents did not divorce (HR: 2.14; 95% CI: 1.33-3.42). There were no consistent findings with adult socio-economic indicators. CONCLUSIONS: There is some evidence of a cumulative effect of socio-economic circumstances in childhood, but not in adulthood, on age at menopause. Childhood nutrition, cognition and emotional stress possibly underlie the social gradient.

Adult↗