Rebecca Moon

Vitamin D supplementation in pregnancy: a systematic review.

BACKGROUND It is unclear whether or not the current evidence base allows definite conclusions to be made regarding the optimal maternal circulating concentration of 25-hydroxyvitamin D [25(OH)D] during pregnancy, and how this might best be achieved. OBJECTIVES To answer the following questions: (1) What are the clinical criteria for vitamin D deficiency in pregnant women? (2) What adverse maternal and neonatal health outcomes are associated with low maternal circulating 25(OH)D? (3) Does maternal supplementation with vitamin D in pregnancy lead to an improvement in these outcomes (including assessment of compliance and effectiveness)? (4) What is the optimal type (D2 or D3), dose, regimen and route for vitamin D supplementation in pregnancy? (5) Is supplementation with vitamin D in pregnancy likely to be cost-effective? METHODS We performed a systematic review and where possible combined study results using meta-analysis to estimate the combined effect size. Major electronic databases [including Database of Abstracts of Reviews of Effects (DARE), Centre for Reviews and Dissemination (CRD), Cochrane Database of Systematic Reviews (CDSR) and the Health Technology Assessment (HTA) database] were searched from inception up to June 2012 covering both published and grey literature. Bibliographies of selected papers were hand-searched for additional references. Relevant authors were contacted for any unpublished findings and additional data if necessary. Abstracts were reviewed by two reviewers. INCLUSION AND EXCLUSION CRITERIA SUBJECTS pregnant women or pregnant women and their offspring. EXPOSURE either assessment of vitamin D status [dietary intake, sunlight exposure, circulating 25(OH)D concentration] or supplementation of participants with vitamin D or food containing vitamin D (e.g. oily fish). OUTCOMES offspring - birthweight, birth length, head circumference, bone mass, anthropometry and body composition, risk of asthma and atopy, small for gestational dates, preterm birth, type 1 diabetes mellitus, low birthweight, serum calcium concentration, blood pressure and rickets; mother - pre-eclampsia, gestational diabetes mellitus, risk of caesarean section and bacterial vaginosis. RESULTS Seventy-six studies were included. There was considerable heterogeneity between the studies and for most outcomes there was conflicting evidence. The evidence base was insufficient to reliably answer question 1 in relation to biochemical or disease outcomes. For questions 2 and 3, modest positive relationships were identified between maternal 25(OH)D and (1) offspring birthweight in meta-analysis of three observational studies using log-transformed 25(OH)D concentrations after adjustment for potential confounding factors [pooled regression coefficient 5.63 g/10% change maternal 25(OH)D, 95% confidence interval (CI) 1.11 to 10.16 g], but not in those four studies using natural units, or across intervention studies; (2) offspring cord blood or postnatal calcium concentrations in a meta-analysis of six intervention studies (all found to be at high risk of bias; mean difference 0.05 mmol/l, 95% CI 0.02 to 0.05 mmol/l); and (3) offspring bone mass in observational studies judged to be of good quality, but which did not permit meta-analysis. The evidence base was insufficient to reliably answer questions 4 and 5. LIMITATIONS Study methodology varied widely in terms of study design, population used, vitamin D status assessment, exposure measured and outcome definition. CONCLUSIONS The evidence base is currently insufficient to support definite clinical recommendations regarding vitamin D supplementation in pregnancy. Although there is modest evidence to support a relationship between maternal 25(OH)D status and offspring birthweight, bone mass and serum calcium concentrations, these findings were limited by their observational nature (birthweight, bone mass) or risk of bias and low quality (calcium concentrations). High-quality randomised trials are now required. STUDY REGISTRATION This study is registered as PROSPERO CRD42011001426. FUNDING The National Institute for Health Research Health Technology Assessment programme.

Maternal plasma polyunsaturated fatty acid status in late pregnancy is associated with offspring body composition in childhood

CONTEXT Maternal diet during pregnancy has been linked to offspring adiposity, but it is unclear whether maternal polyunsaturated fatty acid (PUFA) status during pregnancy affects offspring body composition. OBJECTIVE We investigated the associations between maternal plasma n-3 and n-6 PUFA status at 34 wk gestation and offspring body composition. DESIGN AND SETTING A prospective United Kingdom population-based mother-offspring cohort, the Southampton Womens Survey (SWS), was studied. PARTICIPANTS A total of 12,583 nonpregnant women were recruited into the SWS, among whom 1987 delivered a baby before December 31, 2003; 293 mother-child pairs had complete measurements of maternal plasma PUFA concentrations in late pregnancy and offspring body composition at both ages 4 and 6 yr. MAIN OUTCOMES MEASURED We measured offspring body composition by dual-energy x-ray absorptiometry, yielding fat mass, lean mass, percentage fat mass, and percentage lean mass. Results are presented as β-coefficients for standardized variables, therefore reflecting the sd change of the outcome for every 1 sd of the predictor. RESULTS After adjustment for maternal factors and child factors including height and duration of breast-feeding, maternal plasma n-6 PUFA concentration positively predicted offspring fat mass at 4 yr (β = 0.14 SD/SD; P = 0.01) and 6 yr (β = 0.11 SD/SD; P = 0.04), but there was no association with offspring lean mass at either age (β = 0.005 SD/SD, P = 0.89; and β = 0.008 SD/SD, P = 0.81, respectively). Maternal plasma n-3 PUFA concentration was not associated with offspring fat mass at 4 yr (β = 0.057 SD/SD; P = 0.34) or 6 yr (β = 0.069 SD/SD; P = 0.21). Maternal plasma n-3 PUFA status was positively associated with offspring lean mass on univariate analysis (4 yr, β = 0.11, P = 0.06; 6 yr, β = 0.14; P = 0.02); however, this was confounded by a positive association with offspring height. CONCLUSIONS This observational study suggests that maternal n-6 PUFA status during pregnancy might influence offspring adiposity in childhood.

Epidemiology of fractures in the United Kingdom 1988–2012: Variation with age, sex, geography, ethnicity and socioeconomic status

UNLABELLED Rates of fracture worldwide are changing. Using the Clinical Practice Research Datalink (CPRD), age, and gender, geographical, ethnic and socioeconomic trends in fracture rates across the United Kingdom were studied over a 24-year period 1988-2012. Previously observed patterns in fracture incidence by age and fracture site were evident. New data on the influence of geographic location, ethnic group and socioeconomic status were obtained. INTRODUCTION With secular changes in age- and sex-specific fracture incidence observed in many populations, and global shifts towards an elderly demography, it is vital for health care planners to have an accurate understanding of fracture incidence nationally. We aimed to present up to date fracture incidence data in the UK, stratified by age, sex, geographic location, ethnicity and socioeconomic status. METHODS The Clinical Practice Research Datalink (CPRD) contains anonymised electronic health records for approximately 6.9% of the UK population. Information comes from General Practitioners, and covers 11.3 million people from 674 practices across the UK, demonstrated to be representative of the national population. The study population consisted of all permanently registered individuals aged ≥18years. Validated data on fracture incidence were obtained from their medical records, as was information on socioeconomic deprivation, ethnicity and geographic location. Age- and sex-specific fracture incidence rates were calculated. RESULTS Fracture incidence rates by age and sex were comparable to those documented in previous studies and demonstrated a bimodal distribution. Substantial geographic heterogeneity in age- and sex adjusted fracture incidence was observed, with rates in Scotland almost 50% greater than those in London and South East England. Lowest rates of fracture were observed in black individuals of both sexes; rates of fragility fracture in white women were 4.7 times greater than in black women. Strong associations between deprivation and fracture risk were observed in hip fracture in men, with a relative risk of 1.3 (95% CI 1.21-1.41) in Index of Multiple Deprivation category 5 (representing the most deprived) compared to category 1. CONCLUSIONS This study presents robust estimates of fracture incidence across the UK, which will aid decisions regarding allocation of healthcare provision to populations of greatest need. It will also assist the implementation and design of strategies to reduce fracture incidence and its personal and financial impact on individuals and health services.

Maternal antenatal vitamin D status and offspring muscle development: findings from the Southampton Women's Survey

CONTEXT Maternal 25-hydroxyvitamin D [25(OH)D] status in pregnancy has been associated with offspring bone development and adiposity. Vitamin D has also been implicated in postnatal muscle function, but little is known about a role for antenatal 25(OH)D exposure in programming muscle development. OBJECTIVE We investigated the associations between maternal plasma 25(OH)D status at 34 weeks of gestation and offspring lean mass and muscle strength at 4 years of age. DESIGN AND SETTING We studied a prospective UK population-based mother-offspring cohort: the Southampton Womens Survey (SWS). PARTICIPANTS Initially, 12,583 nonpregnant women were recruited into the SWS, of whom 3159 had singleton pregnancies; 678 mother-child pairs were included in this analysis. MAIN OUTCOMES MEASURED At 4 years of age, offspring assessments included hand grip strength and whole-body dual-energy x-ray absorptiometry, yielding lean mass and percent lean mass. Physical activity was assessed by 7-day accelerometry in a subset of children (n=326). RESULTS The maternal serum 25(OH)D concentration in pregnancy was positively associated with offspring height-adjusted hand grip strength (β=0.10 SD/SD, P=.013), which persisted after adjustment for maternal confounding factors, duration of breastfeeding, and childs physical activity at 4 years (β=0.13 SD/SD, P=.014). Maternal 25(OH)D was also positively associated with offspring percent lean mass (β=0.11 SD/SD, P=.006), but not total lean mass (β=0.06 SD/SD, P=.15). However, this association did not persist after adjustment for confounding factors (β=0.09 SD/SD, P=.11). CONCLUSIONS This observational study suggests that intrauterine exposure to 25(OH)D during late pregnancy might influence offspring muscle development through an effect primarily on muscle strength rather than on muscle mass.

Identifying targets to reduce the incidence of diabetic ketoacidosis at diagnosis of type 1 diabetes in the UK

Background Diabetic ketoacidosis (DKA) is the leading cause of mortality in childhood diabetes, and at diagnosis might represent delayed presentation. The extent and reasons for delays are unclear, but identifying and targeting factors associated with DKA could reduce this incidence. Objective To compare the patient pathway before diagnosis of type 1 diabetes mellitus (T1DM) in children presenting with DKA and non-acidotic hyperglycaemia. Design, setting and patients Over a 3-month period, children newly diagnosed with T1DM were identified on admission to UK hospitals. Parents and medical teams completed a questionnaire about events before diagnosis. Results Data were available for 261 children (54% male), median age 10.3y (range 0.8–16.6 y). 25% presented with DKA, but more commonly in children <2y (80% vs 23%, p<0.001). Fewer children with DKA reported polyuria (76% vs 86%) or polydipsia (86% vs 94%) (both p<0.05), but more reported fatigue (74% vs 52%) and weight loss (75% vs 54%) (both p<0.01). 24% of children had multiple healthcare professional (HCP) contacts, and these children had lower pH on admission. 46% of children with a delayed presentation to secondary care had non-urgent investigations. 64% of parents had considered a diagnosis of diabetes, and these children were less likely to present with DKA (13% vs 47%, p<0.001). Conclusions Multiple HCP contacts increased risk of presentation in DKA, whereas, parental awareness of diabetes was protective. Improved public and health professional education targeting non-classical symptoms, awareness of diabetes in under 2 y, and point-of-care testing could reduce DKA at diagnosis of diabetes.

Pituitary function at long-term follow up of childhood traumatic brain injury

Pituitary dysfunction is a recognized sequela of traumatic brain injury (TBI), occurring in 10-83% of adult patients, but there are few data on the prevalence or natural history in childhood. Our objective was to determine pituitary function in children and young adults at least 4 years after TBI requiring pediatric intensive care unit (PICU) admission. The effects of TBI and hypopituitarism on height, adiposity, and quality of life (QOL) were also evaluated. Unselected patients discharged from the regional PICU with TBI (age < 18 years at injury) from 1999-2004 were recruited. Blood and urine samples were collected for baseline pituitary function testing. Height and weight were measured. Adiposity was assessed by mid-upper arm and waist circumferences, and body fat percentage estimation using four-site skinfold thickness and bioelectrical impedance. Auxology and adiposity data were compared to local age- and sex-matched healthy control data. QOL questionnaires (PedsQL 4.0 and QOL-AGHDA) were completed. Twenty subjects (median age 16.7 years, range 9.2-23.3 years, 13 male) of 127 who were eligible agreed to participate at a median of 6.8 years (range 4.2-10.3 years) since TBI. Markers of injury were higher in those recruited than those who were not. Biochemical evidence of hypopituitarism was identified in only one case, possibly related to comorbid pre-existing attention deficit-hyperactivity disorder. Height, weight, and adiposity were similar to healthy controls. Poor QOL was seen in patients with chronic functional deficits or comorbidities. Overall, pituitary dysfunction was less prevalent than in previous studies in adults and children. The results of this study do not support the use of routine endocrine evaluation of children following TBI.

The impact of fragility fracture and approaches to osteoporosis risk assessment worldwide.

Osteoporosis constitutes a major public health problem, through its association with age-related fractures, particularly of the hip, vertebrae, distal forearm and humerus. Substantial geographic variation has been noted in the incidence of osteoporotic fractures worldwide, with Western populations (North America, Europe and Oceania), reporting increases in hip fracture throughout the second half of the 20th century, with a stabilisation or decline in the last two decades. In developing populations however, particularly in Asia, the rates of osteoporotic fracture appears to be increasing. The massive global burden consequent to osteoporosis means that fracture risk assessment should be a high priority among health measures considered by policy makers. The WHO operational definition of osteoporosis, based on a measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), has been used globally since the mid-1990s. However, although this definition identifies those at greatest individual risk of fracture, in the population overall a greater total number of fractures occur in individuals with BMD values above the threshold for osteoporosis diagnosis. A number of web-based tools to enable the inclusion of clinical risk factors, with or without BMD, in fracture prediction algorithms have been developed to improve the identification of individuals at high fracture risk, the most commonly used globally being FRAX®. Access to DXA, osteoporosis risk assessment, case finding and treatment varies worldwide, but despite such advances studies indicate that a minority of men and women at high fracture risk receive treatment. Importantly, research is ongoing to demonstrate the clinical efficacy and cost-effectiveness of osteoporosis case finding and risk assessment strategies worldwide. The huge burden caused by osteoporosis related fractures to individuals, healthcare systems and societies should provide a clear impetus for the progression of such approaches.

Vitamin D and skeletal health in infancy and childhood.

During growth, severe vitamin D deficiency in childhood can result in symptomatic hypocalcaemia and rickets. Despite the suggestion from some studies of a secular increase in the incidence of rickets, this observation may be driven more by changes in population demographics than a true alteration to age, sex and ethnicity-specific incidence rates; indeed, rickets remains uncommon overall and is rarely seen in fair-skinned children. Additionally, the impact of less severe vitamin D deficiency and insufficiency has received much interest in recent years, and in this review, we consider the evidence relating vitamin D status to fracture risk and bone mineral density (BMD) in childhood and adolescence. We conclude that there is insufficient evidence to support the suggestion that low serum 25-hydroxyvitamin D [25(OH)D] increases childhood fracture risk. Overall, the relationship between 25(OH)D and BMD is inconsistent across studies and across skeletal sites within the same study; however, there is evidence to suggest that vitamin D supplementation in children with the lowest levels of 25(OH)D might improve BMD. High-quality randomised trials are now required to confirm this benefit.

Recent advances in the pathogenesis and treatment of osteoporosis.

Over recent decades, the perception of osteoporosis has changed from that of an inevitable consequence of ageing, to that of a well characterised and treatable chronic non-communicable disease, with major impacts on individuals, healthcare systems and societies. Characterisation of its pathophysiology from the hierarchical structure of bone and the role of its cell population, development of effective strategies for the identification of those most appropriate for treatment, and an increasing armamentarium of efficacious pharmacological therapies, have underpinned this evolution. Despite this marked progress, individuals who experience a fragility fracture remain under-treated in many areas of the world, and there is substantial need for investment both in secondary and primary prevention globally. In this brief article, we give an overview of the pathogenesis of osteoporosis, and summarise current and future approaches to its assessment and treatment.

ENDOCRINOLOGY IN PREGNANCY: Influence of maternal vitamin D status on obstetric outcomes and the fetal skeleton

Vitamin D status has been increasingly associated with wide-ranging clinical outcomes. There is now a wealth of observational studies reporting on its associations with obstetric complications, including pre-eclampsia, gestational diabetes and the mode and timing of delivery. The findings are inconsistent, and currently there is a lack of data from high-quality intervention studies to confirm a causal role for vitamin D in these outcomes. This is similarly true with regards to fetal development, including measures of fetal size and skeletal mineralisation. Overall, there is an indication of possible benefits of vitamin D supplementation during pregnancy for offspring birthweight, calcium concentrations and bone mass as well as for reduced maternal pre-eclampsia. However, for none of these outcomes is the current evidence base conclusive, and the available data justify the instatement of high-quality randomised placebo controlled trials in a range of populations and health care settings to establish the potential efficacy and safety of vitamin D supplementation to improve particular outcomes.