Showing papers by "Mark S. Pearce published in 2011"

Managing Radiation Use in Medical Imaging: A Multifaceted Challenge

Abstract: Summarized here are the nature and extent of the many challenges involved in managing the radiation exposure from medical imaging in a way that maximizes the benefit-risk ratio for every patient.

Longitudinal Study of Physical Activity and Sedentary Behavior in Children

Abstract: OBJECTIVE: Physical activity is thought to decline during childhood, but the extent of the decline is unknown. We made objective measures of 2-year changes in physical activity and sedentary behavior in English children who participated in the Gateshead Millennium Study to explore the nature, timing, and extent of changes in physical activity and sedentary behavior before adolescence. METHODS: We conducted a longitudinal study of 405 children (207 girls), aged 7 years, in 2006/2007 and again 24 months later. Physical activity and sedentary behavior were measured with the Actigraph GT1M accelerometer. Data were analyzed in 2010. Changes in total volume of physical activity (accelerometer counts per minute [cpm]), moderate-to-vigorous–intensity physical activity (MVPA), and sedentary behavior were quantified. Factors associated with changes in physical activity and sedentary behavior were tested by using linear regression. Tracking of physical activity and sedentary behavior over the 2-year period was assessed by rank-order correlation. RESULTS: Mean daily volume of physical activity declined by 83 cpm (interquartile range [IQR]: −189 to 31) over 2 years; the percentage of daily time spent in MVPA was low at baseline and declined by 0.3% (IQR: −1.4 to 0.9). The percentage of daily time in sedentary behavior was high at baseline and increased from 78.0% to 81.1% of the day (change 3.1% [IQR: −0.3 to 6.0]). The decline in MVPA and increase in sedentary behavior were significantly greater in girls and in those with higher BMI z scores at baseline. Physical activity and sedentary behavior showed moderate tracking over the 2-year period. CONCLUSIONS: We report here new evidence of low and declining levels of physical activity and MVPA and increasing sedentary behavior before adolescence.

Parental perceptions of weight status in children: the Gateshead Millennium Study.

Abstract: To investigate parents’ perceptions of weight status in children and to explore parental understanding of and attitudes to childhood overweight Questionnaires and focus groups within a longitudinal study 536 parents of Gateshead Millennium Study children, of which 27 attended six focus groups Parents’ perception of their child's weight status according to actual weight status as defined by International Obesity Taskforce (IOTF) cutoffs Focus group outcomes included parental awareness of childhood overweight nationally and parental approaches to identifying overweight children The sensitivity of parents recognising if their child was overweight was 031 Prevalence of child overweight was underestimated: 73% of children were perceived as ‘overweight’ or ‘very overweight’ by their parents, 237% were identified as overweight or obese using IOTF criteria 693% of parents of overweight or obese children identified their child as being of ‘normal’ weight During focus groups parents demonstrated an awareness of childhood overweight being a problem nationally but their understanding of how it is defined was limited Parents used alternative approaches to objective measures when identifying overweight in children such as visual assessments and comparisons with other children Such approaches relied heavily on extreme and exceptional cases as a reference point The apparent lack of relevance of childhood overweight to their child's school or own community along with scepticism towards both media messages and clinical measures commonly emerged as grounds for failing to engage with the issue at a personal level Parents’ ability to identify when their child was overweight according to standard criteria was limited Parents did not understand, use or trust clinical measures and used alternative approaches primarily reliant on extreme cases Such approaches underpinned their reasoning for remaining detached from the issue This study highlights the need to identify methods of improving parental recognition of and engagement with the problem of childhood overweight

Neonatal and Delivery Outcomes in Women with Multiple Sclerosis

Abstract: Multiple sclerosis (MS) is a chronic degenerative disease of the central nervous system and the most common cause of nontraumatic neurological disability in young adults in Europe and North America. Around 75% of people with MS are women, and clinical onset most often occurs in early adulthood, just when many are considering starting a family. Studies have shown that between ⅕ and ⅓ of women with MS bear children after disease onset,1, 2 making the effect of maternal MS on pregnancy outcomes relevant to patients, their family members, and health care professionals. During the 1990s, research on pregnancy outcomes in MS mothers was generally undertaken as a secondary aspect of investigations of the effect of pregnancy on disability and exacerbations of the disease around the time of pregnancy. Studies examining pregnancy outcomes from this period were small,3, 4 and findings were for the most part descriptive. More recently, several larger studies examining pregnancy outcomes in MS5–9 have shown conflicting results. Previous studies also had limited ability to control for many potentially confounding factors and often relied on populating the MS group using only International Classification of Diseases (ICD) codes rather than having clinically defined groups of patients, leading to potential misclassification of study participants or selection of individuals with MS with more severe disease. We linked data from the British Columbia (BC) MS Clinics' database with the BC Perinatal Database Registry (BCPDR) to examine whether maternal MS was associated with adverse neonatal and delivery outcomes and whether risk was associated with age at disease onset, disease duration, or disability.

Stability of habitual physical activity and sedentary behaviour monitoring by accelerometry in 6-8 year olds

Abstract: Background: Accelerometry is rapidly becoming the instrument of choice for measuring physical activity in children. However, as limited data exist on the minimum number of days accelerometry required to provide a reliable estimate of habitual physical activity, we aimed to quantify the number of days of recording required to estimate both habitual physical activity and habitual sedentary behavior in primary school children. Methods: We measured physical activity and sedentary behavior over 7 days in 291 6- to 8-year-olds using Actigraph accelerometers. Between-day intraclass reliability coefficients were calculated and averaged across all combinations of days. Results: Although reliability increased with time, 3 days of recording provided reliabilities for volume of activity, moderate-vigorous intensity activity, and sedentary behavior of 68%, 71%, and 73%, respectively. Conclusions: For our sample and setting, 3 days accelerometry provided reliable estimates of the main constructs of physical activity an...

Reliability and validity of ultrasound imaging of features of knee osteoarthritis in the community

Abstract: Radiographs are the main outcome measure in epidemiological studies of osteoarthritis (OA). Ultrasound imaging has unique advantages in that it involves no ionising radiation, is easy to use and visualises soft tissue structures. Our objective was to measure the inter-rater reliability and validity of ultrasound imaging in the detection of features of knee OA. Eighteen participants from a community cohort, had both knees scanned by two trained musculoskeletal sonographers, up to six weeks apart. Inter-rater reliability for osteophytes, effusion size and cartilage thickness was calculated by estimating Kappa (κ) and Intraclass correlation coefficients (ICC), as appropriate. A measure of construct validity was determined by estimating κ between the two imaging modalities in the detection of osteophytes. Reliability: κ for osteophyte presence was 0.77(right femur), 0.65(left femur) and 0.88 for both tibia. ICCs for effusion size were 0.70(right) and 0.85(left). Moderate to substantial agreement was found in cartilage thickness measurements. Validity: For osteophytes, κ was moderate to excellent at 0.52(right) and 0.75(left). Substantial to excellent agreement was found between ultrasound observers for the presence of osteophytes and measurement of effusion size; it was moderate to substantial for femoral cartilage thickness. Moderate to substantial agreement was observed between ultrasound and radiographs for osteophyte presence.

Cohort profile: the Gateshead Millennium Study.

Abstract: The Gateshead Millennium Baby Study (GMBS) originated from the observation that slower than expected weight gain in infancy, traditionally known as failure to thrive, but more recently as ‘weight faltering’, had never been satisfactorily explained. There were methodological problems associated with much previous research. The first was the use of attained weight criteria to identify slow weight gain in infancy, which confounds poor postnatal weight gain with poor prenatal weight gain. The second was the use of referred samples of children, leading to selection biases. The third was the use of retrospective accounts from parents after poor weight gain had already been identified. The GMBS was thus originally designed to investigate the antecedents of weight faltering in a population-based prospective study that addressed the main methodological problems of previous research.

The influence of childhood IQ and education on social mobility in the Newcastle Thousand Families birth cohort

Abstract: It has been suggested that social, educational, cultural and physical factors in childhood and early adulthood may influence the chances and direction of social mobility, the movement of an individual between social classes over his/her life-course. This study examined the association of such factors with intra-generational and inter-generational social mobility within the Newcastle Thousand Families 1947 birth cohort. Multivariable logistic regression was used to examine the potential association of sex, housing conditions at age 5 years, childhood IQ, achieved education level, adult height and adverse events in early childhood with upward and downward social mobility. Childhood IQ and achieved education level were significantly and independently associated with upward mobility between the ages of 5 and 49-51 years. Only education was significantly associated (positively) with upward social mobility between 5 and 25 years, and only childhood IQ (again positively) with upward social mobility between 25 and 49-51 years. Childhood IQ was significantly negatively associated with downward social mobility. Adult height, childhood housing conditions, adverse events in childhood and sex were not significant determinants of upward or downward social mobility in this cohort. As upward social mobility has been associated with better health as well as more general benefits to society, supportive measures to improve childhood circumstances that could result in increased IQ and educational attainment may have long-term population health and wellbeing benefits.

Patterns in paediatric CT use: an international and epidemiological perspective

Abstract: Since the introduction of CT imaging for use in medicine in the early 1970s, its use has increased rapidly throughout the world. While the immediate benefit to the individual patient of having a CT scan can be substantial, the relatively high radiation doses associated with CT have given rise to concerns regarding a possible increase in future cancer risk.1–5 However, the risk estimation studies to date are based on extrapolations and fraught with uncertainties regarding doses and whether accurate numbers of CT scans can be estimated, particularly when rates of CT imaging are likely to vary by country, by sex, by age group and by the part(s) of the body that require imaging. Children can receive higher radiation doses than necessary, particularly if scanned using adult CT settings. Surveys have estimated that children under 15 years of age make up between 3 and 11% of patients who undergo CT examinations in societies with the highest level of health care.6–8 Suggestions have been made in a number of settings that the use of CT imaging is not always justified in young patients,9 with frequent calls to follow the as low as reasonably achievable (ALARA) principle10,11 and the ‘image gently’ initiative.12 The latter is an initiative of the ‘Alliance for Radiation Safety in Pediatric Imaging’ aimed specifically at raising awareness of the need and opportunities to reduce radiation exposures to children undergoing medical imaging.12 Further, a recent editorial in this journal highlighted the likely causes and consequences of inappropriate imaging in Australia.13 The concerns regarding CT imaging in young people, coupled with the fact that few empirical data have been used in existing risk predictions, make this an area of epidemiological research of great importance. Further, most prediction models and previous studies of trends in CT usage have been based on adult patients or whole populations with no breakdown by age group, whereas the greatest concern is for children and those undergoing multiple examinations. Given the increases seen in CT imaging for entire populations covering all age groups, an important question is whether the same is true for children. In this issue, Brady et al.14 present trends over 20 years in the use of paediatric CT, using data from Medicare and from the Royal Children’s Hospital, Melbourne, the only hospital in the state of Victoria dedicated to paediatric patients. The data accessed for the study include that on the type and date of the CT examination(s), the age and sex of each patient, and for the final 10 years of the study, billing code data. Using population data, Brady et al. were able to report rates of CT usage, rather than just frequencies. Over a 15-year period, the rate of children (aged 0–18 years) scanned rose from 6.3 to 13.3%. There was a near tripling of use based on the number of services billed to Medicare over the same time period and a slightly lower increase in usage at the Royal Children’s Hospital. While CT examinations were more common in male than in female Journal of Medical Imaging and Radiation Oncology 55 (2011) 107–109

CT scans in young people in Northern England: trends and patterns 1993–2002

Abstract: Background Although CT can be greatly beneficial, its relatively high radiation doses have caused public health concerns.

The relatively small contribution of birth weight to blood pressure at age 49-51 years in the Newcastle Thousand Families Study.

Abstract: BackgroundWhereas a large number of previous studies suggest an association between birth weight and later blood pressure, others do not. Controversy surrounds the relative importance of these associations, in particular in relation to more modifiable factors in later life. The aim of this study was

Space?time clustering of elevated thyroid stimulating hormone levels

Abstract: Previous studies of congenital hypothyroidism (CHT) have reported an increasing incidence which may suggest that environmental factors play an aetiological role. If so, then cases may exhibit space–time clustering, where cases occur at similar times and close proximities to other cases. In this study we investigated whether space–time clustering of elevated thyroid stimulating hormone (TSH) in newborns exists. All infants born in the Northern Region of England are screened by measuring levels of circulating TSH using a blood spot assay. Data on 207 cases of elevated TSH values, as a proxy for CHT, in newborns born from 1994 to 2006 inclusive were available and analysed using rigorous space–time clustering statistical methods. Analysis showed statistically significant evidence of space–time clustering. The strength of clustering was most marked for cases born within 0.1–0.7 year (1–8 months) of one another. This is the first study to find significant space–time clustering of cases of elevated TSH levels in newborns, a surrogate for space–time clustering of CHT. Whilst the reasons for the clustering are unclear, it would appear from this analysis that transient environmental exposures are likely to be involved, although environmental determinants of genetic mutations and epigenetic factors cannot be ruled out. Further research is required to a) validate these results in other populations and b) to assess in more detail the potential environmental determinants of increased CHT risk.

Birth weight and early socio-economic disadvantage as predictors of sex hormones and sex hormone binding globulin in men at age 49-51 years.

Abstract: Objectives: A number of associations have been shown between early growth and later sex hormone levels in women, but less is known about this relationship in men. This study investigated lifecourse predictors of sex hormones in men in the Newcastle Thousand Families birth cohort. Methods: The Newcastle Thousand Families Study is a prospective study initiated in 1947. At age 49-51 years, 574 study members returned detailed self-completion questionnaires and 412 attended for clinical examination, including 172 men in whom blood samples were taken. Estradiol, follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and sex hormone binding globulin (SHBG) were measured. Free testosterone concentrations were also calculated. Results: Social class at birth independently predicted FSH and LH, with higher levels with increasing socioeconomic disadvantage. SHBG was higher with increasing standardized birth weight and lower with increasing contemporary body mass index (BMI). BMI also predicted LH, SHBG, and testosterone. None of the variables included within this analysis were significant predictors of estradiol. No other associations were seen with any of the variables included from across the lifecourse. Conclusions: Our findings suggest that birth weight may be positively associated with SHBG and early socioeconomic status may be related to FSH and LH in men. These novel findings are independent of contemporary BMI. Given the links between sex hormones, SHBG and disease outcomes such as type II diabetes and osteoporosis, it is possible that sex hormones may play a mediating role in the associations between circumstances in early life and later risk of chronic disease.

Birth weight by gestational age and risk of childhood acute leukemia: a population-based study 1961–2002

Abstract: There is evidence to suggest that childhood leukemia may be initiated in utero [1]. One of the perinatal factors found to be associated with an increased risk of childhood acute leukemia (CAL) is h...

Long term cardiovascular risk in women with pre-eclampsia: systematic review and meta-analysis

Abstract: Introduction There is increasing evidence that pre-eclampsia, a principal cause of maternal morbidity, may also be a risk factor for future cardiovascular and cerebrovascular events. This review aimed to assess the current evidence and quantify the risks of cardiovascular and cerebrovascular events that may follow a diagnosis of pre-eclampsia. Methods MEDLINE and EMBASE were searched with no language restrictions, as were core journals and reference lists from reviews. Case control and cohort studies which reported cardiovascular and cerebrovascular diseases diagnosed more than 6 weeks postpartum, in women who had history of pre-eclampsia relative to women who had unaffected pregnancies, were included. Results 24 articles were included in the systematic review and 19 in the meta-analysis. Women with a history of pre-eclampsia or eclampsia were at significantly increased odds of fatal or non-fatal cardiovascular disease (OR=2.27, 95% CI 1.83 to 2.82) and cerebrovascular disease (OR=2.46, 95% CI 1.57 to 3.85). Among pre-eclamptic women, pre-term delivery was not associated with an increased risk of a future cardiovascular event (relative risk=1.28, 95% CI 0.82 to 1.99). Conclusion Women diagnosed with pre-eclampsia are at increased risk of future cardiovascular or cerebrovascular events, with an estimated doubling of risk compared to unaffected women. This has implications for the follow-up of all women who experience pre-eclampsia, not just those who deliver pre-term. This association may reflect shared common risk factors for both pre-eclampsia and cardiovascular and cerebrovascular disease.

P1-533 Trends in prevalence, pregnancy outcome, and survival of children born with Spina Bifida

Abstract: Introduction Spina bifida is a serious congenital anomaly associated with life-long disability. This study describes trends in the prevalence and survival of spina bifida, to 10 years, using data from a long-standing congenital anomaly register in Northern England. Methods Cases of isolated spina bifida, delivered during 1985–2003, were identified from the population-based Northern Congenital Abnormality Survey (NorCAS). Survival status was determined from local to national records. Trends in prevalence and survival were examined by the Cochran-Armitage test and by Cox regression respectively. Results 500 cases of spina bifida were identified during the study, including 196 (39%) live born cases. The total prevalence of spina bifida was 7.5 (95% CI 6.9 to 8.2) per 10 000 total births, while the live born prevalence was 3.0 (95% CI 2.6 to 3.4) per 10 000 live births. Total prevalence decreased over time from 9.6 (95% CI 8.4 to 11.0) per 10 000 total births in 1985–1990 to 5.8 (95% CI 4.8 to 6.9) per 10 000 total births in 1997–2003 (p Conclusions The prevalence of spina bifida has decreased over time while survival for live born cases has significantly increased. These data are important for counselling families when a spina bifida is detected and for health service planning.