Abigail Fraser

The Avon Longitudinal Study of Parents and Children (ALSPAC) is a transgenerational prospective observational study investigating influences on health and development across the life course. It considers multiple genetic, epigenetic, biological, psychological, social and other environmental exposures in relation to a similarly diverse range of health, social and developmental outcomes. Recruitment sought to enroll pregnant women in the Bristol area of the UK during 1990-92; this was extended to include additional children eligible using the original enrollment definition up to the age of 18 years. The children from 14541 pregnancies were recruited in 1990-92, increasing to 15247 pregnancies by the age of 18 years. This cohort profile describes the index children of these pregnancies. Follow-up includes 59 questionnaires (4 weeks-18 years of age) and 9 clinical assessment visits (7-17 years of age). The resource comprises a wide range of phenotypic and environmental measures in addition to biological samples, genetic (DNA on 11343 children, genome-wide data on 8365 children, complete genome sequencing on 2000 children) and epigenetic (methylation sampling on 1000 children) information and linkage to health and administrative records. Data access is described in this article and is currently set up as a supported access resource. To date, over 700 peer-reviewed articles have been published using ALSPAC data.

Summary The Avon Longitudinal Study of Children and Parents (ALSPAC) was established to understand how genetic and environmental characteristics influence health and development in parents and children. All pregnant women resident in a defined area in the South West of England, with an expected date of delivery between 1st April 1991 and 31st December 1992, were eligible and 13761 women (contributing 13867 pregnancies) were recruited. These women have been followed over the last 19-22 years and have completed up to 20 questionnaires, have had detailed data abstracted from their medical records and have information on any cancer diagnoses and deaths through record linkage. A follow-up assessment was completed 17-18 years postnatal at which anthropometry, blood pressure, fat, lean and bone mass and carotid intima media thickness were assessed, and a fasting blood sample taken. The second follow-up clinic, which additionally measures cognitive function, physical capability, physical activity (with accelerometer) and wrist bone architecture, is underway and two further assessments with similar measurements will take place over the next 5 years. There is a detailed biobank that includes DNA, with genome-wide data available on >10000, stored serum and plasma taken repeatedly since pregnancy and other samples; a wide range of data on completed biospecimen assays are available. Details of how to access these data are provided in this cohort profile.

BACKGROUND & AIMS: Narrative reviews of paediatric NAFLD quote prevalences in the general population that range from 9% to 37%; however, no systematic review of the prevalence of NAFLD in children/adolescents has been conducted. We aimed to estimate prevalence of non-alcoholic fatty liver disease (NAFLD) in young people and to determine whether this varies by BMI category, gender, age, diagnostic method, geographical region and study sample size. METHODS: We conducted a systematic review and meta-analysis of all studies reporting a prevalence of NAFLD based on any diagnostic method in participants 1-19 years old, regardless of whether assessing NAFLD prevalence was the main aim of the study. RESULTS: The pooled mean prevalence of NAFLD in children from general population studies was 7.6% (95%CI: 5.5% to 10.3%) and 34.2% (95% CI: 27.8% to 41.2%) in studies based on child obesity clinics. In both populations there was marked heterogeneity between studies (I2 = 98%). There was evidence that prevalence was generally higher in males compared with females and increased incrementally with greater BMI. There was evidence for differences between regions in clinical population studies, with estimated prevalence being highest in Asia. There was no evidence that prevalence changed over time. Prevalence estimates in studies of children/adolescents attending obesity clinics and in obese children/adolescents from the general population were substantially lower when elevated alanine aminotransferase (ALT) was used to assess NAFLD compared with biopsies, ultrasound scan (USS) or magnetic resonance imaging (MRI). CONCLUSIONS: Our review suggests the prevalence of NAFLD in young people is high, particularly in those who are obese and in males.

BACKGROUND: Bacterial infections are a major cause of illness and death in patients who are neutropenic after chemotherapy treatment for cancer. Trials have shown the efficacy of antibiotic prophylaxis in decreasing the incidence of bacterial infections but not in reducing mortality rates. PURPOSE: To evaluate whether antibiotic prophylaxis in neutropenic patients reduces mortality and incidence of infection and to assess related adverse events. DATA SOURCES: The Cochrane Cancer Network register of trials (2004), The Cochrane Library (Issue 4, 2004), EMBASE (1980-2004), MEDLINE (1966-2004), and references of identified studies. STUDY SELECTION: Randomized, controlled trials comparing antibiotic prophylaxis with placebo or no intervention or another antibiotic in afebrile neutropenic patients. DATA EXTRACTION: Two reviewers independently appraised the quality of trials and extracted data. DATA SYNTHESIS: Ninety-five trials performed between 1973 and 2004 met inclusion criteria. Fifty-two trials addressed quinolone prophylaxis. Antibiotic prophylaxis significantly decreased the risk for death when compared with placebo or no treatment (relative risk, 0.67 [95% CI, 0.55 to 0.81]). All prophylactic antibiotics were associated with an increased risk for adverse events (relative risk, 1.69 [CI, 1.14 to 2.50]). Fluoroquinolone prophylaxis reduced the risk for all-cause mortality (relative risk, 0.52 [CI, 0.35 to 0.77]), as well as infection-related mortality, fever, clinically documented infections, and microbiologically documented infections. Fluoroquinolone prophylaxis increased the risk for harboring bacilli resistant to the specific drug after treatment and adverse events, but these results were not statistically significant (relative risks, 1.69 [CI, 0.73 to 3.92]) and 1.30 [CI, 0.61 to 2.76], respectively). LIMITATIONS: Most trials involved patients with hematologic cancer. Data on all-cause mortality were missing in 10 of 50 trials comparing prophylaxis with no prophylaxis. Effect estimates were larger in trials of unclear methodologic quality compared with trials of adequate methodologic quality. CONCLUSIONS: Antibiotic prophylaxis for neutropenic patients undergoing cytotoxic therapy reduces mortality. Mortality was substantially reduced when analysis was limited to fluoroquinolones. Antibiotic prophylaxis, preferably with a fluoroquinolone, should be considered for neutropenic patients.

BACKGROUND: We sought to examine the association of gestational weight gain (GWG) and prepregnancy weight with offspring adiposity and cardiovascular risk factors. METHODS AND RESULTS: Data from 5154 (for adiposity and blood pressure) and 3457 (for blood assays) mother-offspring pairs from a UK prospective pregnancy cohort were used. Random-effects multilevel models were used to assess incremental GWG (median and range of repeat weight measures per woman: 10 [1, 17]). Women who exceeded the 2009 Institute of Medicine-recommended GWG were more likely to have offspring with greater body mass index, waist, fat mass, leptin, systolic blood pressure, C-reactive protein, and interleukin-6 levels and lower high-density lipoprotein cholesterol and apolipoprotein A1 levels. Children of women who gained less than the recommended amounts had lower levels of adiposity, but other cardiovascular risk factors tended to be similar in this group to those of offspring of women gaining recommended amounts. When examined in more detail, greater prepregnancy weight was associated with greater offspring adiposity and more adverse cardiovascular risk factors at age 9 years. GWG in early pregnancy (0 to 14 weeks) was positively associated with offspring adiposity across the entire distribution but strengthened in women gaining >500 g/wk. By contrast, between 14 and 36 weeks, GWG was only associated with offspring adiposity in women gaining >500 g/wk. GWG between 14 and 36 weeks was positively and linearly associated with adverse lipid and inflammatory profiles, with these associations largely mediated by the associations with offspring adiposity. CONCLUSIONS: Greater maternal prepregnancy weight and GWG up to 36 weeks of gestation are associated with greater offspring adiposity and adverse cardiovascular risk factors. Before any GWG recommendations are implemented, the balance of risks and benefits of attempts to control GWG for short- and long-term outcomes in mother and child should be ascertained.