The InterLACE study: Design, data harmonization and characteristics across 20 studies on women's health.
OBJECTIVE
The International Collaboration for a Life Course Approach to Reproductive Health and Chronic Disease Events (InterLACE) project is a global research collaboration that aims to advance understanding of women's reproductive health in relation to chronic disease risk by pooling individual participant data from several cohort and cross-sectional studies. The aim of this paper is to describe the characteristics of contributing studies and to present the distribution of demographic and reproductive factors and chronic disease outcomes in InterLACE.


METHODS
InterLACE is an individual-level pooled study of 20 observational studies (12 of which are longitudinal) from ten countries. Variables were harmonized across studies to create a new and systematic synthesis of life-course data.


METHODS
Harmonized data were derived in three domains: 1) socio-demographic and lifestyle factors, 2) female reproductive characteristics, and 3) chronic disease outcomes (cardiovascular disease (CVD) and diabetes).


RESULTS
InterLACE pooled data from 229,054 mid-aged women. Overall, 76% of the women were Caucasian and 22% Japanese; other ethnicities (of 300 or more participants) included Hispanic/Latin American (0.2%), Chinese (0.2%), Middle Eastern (0.3%), African/black (0.5%), and Other (1.0%). The median age at baseline was 47 years (Inter-quartile range (IQR): 41-53), and that at the last follow-up was 56 years (IQR: 48-64). Regarding reproductive characteristics, half of the women (49.8%) had their first menstruation (menarche) at 12-13 years of age. The distribution of menopausal status and the prevalence of chronic disease varied considerably among studies. At baseline, most women (57%) were pre- or peri-menopausal, 20% reported a natural menopause (range 0.8-55.6%) and the remainder had surgery or were taking hormones. By the end of follow-up, the prevalence rates of CVD and diabetes were 7.2% (range 0.9-24.6%) and 5.1% (range 1.3-13.2%), respectively.


CONCLUSIONS
The scale and heterogeneity of InterLACE data provide an opportunity to strengthen evidence concerning the relationships between reproductive health through life and subsequent risks of chronic disease, including cross-cultural comparisons.
School of Public Health, The University of Queensland, Brisbane, Queensland, Australia. Electronic address: g.mishra@uq.edu.au.
Gita D
GD
Mishra
School of Public Health, The University of Queensland, Brisbane, Queensland, Australia.
Hsin-Fang
HF
Chung
School of Public Health, The University of Queensland, Brisbane, Queensland, Australia.
Nirmala
N
Pandeya
School of Public Health, The University of Queensland, Brisbane, Queensland, Australia.
Annette J
AJ
Dobson
School of Public Health, The University of Queensland, Brisbane, Queensland, Australia.
Lee
L
Jones
Department of Social Sciences and Health Policy, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC, USA.
Nancy E
NE
Avis
Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
Sybil L
SL
Crawford
Department of Public Health Sciences, University of California Davis, Davis, CA, USA.
Ellen B
EB
Gold
Department of Anthropology, University of Hawaii, Hilo, HI, USA.
Daniel
D
Brown
Department of Anthropology, UMass Amherst, Amherst, MA, USA.
Lynette L
LL
Sievert
Department of Epidemiology and Public Health, University College London, London, UK.
Eric
E
Brunner
Nutritional Epidemiology Group, School of Food Science and Nutrition, University of Leeds, Leeds, UK.
Janet E
JE
Cade
Nutritional Epidemiology Group, School of Food Science and Nutrition, University of Leeds, Leeds, UK.
Victoria J
VJ
Burley
Nutritional Epidemiology Group, School of Food Science and Nutrition, University of Leeds, Leeds, UK.
Darren C
DC
Greenwood
Cancer Epidemiology Center, Cancer Council Victoria, Melbourne, Victoria, Australia.
Graham G
GG
Giles
Cancer Epidemiology Center, Cancer Council Victoria, Melbourne, Victoria, Australia.
Fiona
F
Bruinsma
Institute of Education, Center for Longitudinal Studies, University of London, London, UK.
Alissa
A
Goodman
School of Health Sciences, Gunma University, Maebashi City, Gunma Prefecture, Japan.
Kunihiko
K
Hayashi
Department of Health Promotion Science, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Jung Su
JS
Lee
Department of Obstetrics and Gynecology, Hirosaki University School of Medicine, Hirosaki, Japan.
Hideki
H
Mizunuma
Medical Research Council Unit for Lifelong Health and Ageing at UCL, London, UK.
Diana
D
Kuh
Medical Research Council Unit for Lifelong Health and Ageing at UCL, London, UK.
Rachel
R
Cooper
Medical Research Council Unit for Lifelong Health and Ageing at UCL, London, UK.
Rebecca
R
Hardy
Center for Research on Population and Health, Faculty of Health Sciences, American University of Beirut, Lebanon.
Carla Makhlouf
CM
Obermeyer
School of Nursing, University of California, San Francisco, CA, USA.
Kathryn A
KA
Lee
Finsencenter, Rigshospitalet, Copenhagan, Denmark.
Mette Kildevæld
MK
Simonsen
Department of Women's Health Nursing Tohoku University Graduate School of Medicine, Sendai Japan.
Toyoko
T
Yoshizawa
Biobehavioral Nursing and Health Systems, School of Nursing, University of Washington, Seattle, WA, USA.
Nancy F
NF
Woods
Family and Child Nursing, School of Nursing, University of Washington, Seattle, WA, USA.
Ellen S
ES
Mitchell
Department of Epidemiology and Public Health, University College London, London, UK.
Mark
M
Hamer
Department of Epidemiology and Public Health, University College London, London, UK.
Panayotes
P
Demakakos
Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden.
Sven
S
Sandin
Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden; Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA.
Hans-Olov
HO
Adami
Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden; Samfundet Folkhälsan, Helsinki, Finland; Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway; Department of Research, Cancer Registry of Norway, Oslo, Norway.
Elisabete
E
Weiderpass
Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia.
Debra
D
Anderson
D000293:Adolescent; D000328:Adult; D044466:Asian People / Q000706:statistics & numerical data; D044383:Black People / Q000706:statistics & numerical data; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000208:ethnology; D002648:Child; D002681:China; D002908:Chronic Disease; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology* / Q000208:ethnology; D005260:Female; D006801:Humans; D007564:Japan; D007843:Latin America; D008019:Life Style; D008572:Menarche; D008593:Menopause; D008875:Middle Aged; D008877:Middle East; D064887:Observational Studies as Topic; D015995:Prevalence; D060728:Reproductive Health; D044465:White People / Q000706:statistics & numerical data; D016387:Women's Health
Baseline characteristics; Chronic disease; Cross-cultural comparison; Harmonization; Life-course research; Reproductive health