title: Folic acid in pregnancy and mortality from cancer and cardiovascular disease: further follow-up of the Aberdeen folic acid supplementation trial.
abstract: BACKGROUND
  Supplemental periconceptional folic acid is recommended to reduce the risk of fetal neural tube defects. A previous report indicated an elevated risk of breast cancer and all cancer deaths in later life among women randomised by alternate allocation to high-dose (5 mg/day) folic acid in pregnancy compared with placebo; however, findings were based on small numbers of cases. Our aim was to extend the previous analysis by including data from an additional 10 years of follow-up.
  
  
  METHODS
  Records of participants in a large (n=2928) trial of folate supplementation (5 or 0.2 mg folic acid, or placebo) in pregnancy in the 1960s were linked to central registries in Scotland. Unadjusted and adjusted HRs were calculated for all-cause, cardiovascular, all cancer and breast cancer mortality, and all cancer and breast cancer morbidity. Analyses were done using (1) data from the time of the previous linkage (2002) to March 2013; and (2) data from 1980 to March 2013.
  
  
  RESULTS
  There was no evidence to suggest an excess risk of morbidity or mortality in either supplementation group compared with placebo for 2002-2013 and no associations were seen for the full time period (1980-2013).
  
  
  CONCLUSIONS
  Findings from this extended follow-up do not support our previous observation of an elevated risk of mortality from breast cancer or all cancers in later life among women who had taken 5 mg folic acid/day during pregnancy. Furthermore, there were no associations with risk of mortality from all-causes, all cancers or cardiovascular disease.
authors: NIHR Biomedical Research Unit in Nutrition, Diet and Lifestyle, University of Bristol, Bristol, UK.
authors: Caroline M
authors: CM
authors: Taylor
authors: NIHR Biomedical Research Unit in Nutrition, Diet and Lifestyle, University of Bristol, Bristol, UK.
authors: Charlotte
authors: C
authors: Atkinson
authors: NIHR Biomedical Research Unit in Nutrition, Diet and Lifestyle, University of Bristol, Bristol, UK.
authors: Chris
authors: C
authors: Penfold
authors: Dugald Baird Centre for Research on Women's Health, University of Aberdeen, Aberdeen Maternity Hospital, Aberdeen, UK.
authors: Sohinee
authors: S
authors: Bhattacharya
authors: Institute of Applied Health Sciences, University of Aberdeen, Aberdeen, UK.
authors: Doris
authors: D
authors: Campbell
authors: MRC Integrative Epidemiology Unit, School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors: George
authors: G
authors: Davey Smith
authors: NIHR Biomedical Research Unit in Nutrition, Diet and Lifestyle, University of Bristol, Bristol, UK.
authors: Sam
authors: S
authors: Leary
authors: NIHR Biomedical Research Unit in Nutrition, Diet and Lifestyle, University of Bristol, Bristol, UK.
authors: Andy
authors: A
authors: Ness
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology / Q000401:mortality*; D002318:Cardiovascular Diseases / Q000139:chemically induced / Q000453:epidemiology / Q000401:mortality*; D002423:Cause of Death; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000009:adverse effects* / Q000494:pharmacology; D005500:Follow-Up Studies; D006397:Hematinics / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D006801:Humans; D000069451:Long Term Adverse Effects / Q000139:chemically induced*; D009369:Neoplasms / Q000139:chemically induced / Q000453:epidemiology / Q000401:mortality; D009436:Neural Tube Defects / Q000517:prevention & control*; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic; D012042:Registries; D012307:Risk Factors; D012606:Scotland
chemical_list: D006397:Hematinics; D005492:Folic Acid
keywords: CANCER; CANCER: BREAST; EPIDEMIOLOGY; MATERNAL HEALTH; MORTALITY