List characteristics of studies included in the federated analysis
| Study | Country; sample; deaths | Year of baseline assessment; mean follow-up | Device; method of sleep time assessment | Method of death ascertainment | Covariates |
| ABC | Sweden; n=841 (370 men, 471 women); 78 deaths | 2001–2002; 14.5 years | ActiGraph 7164 (lower back); NA | National death register | Age, sex, education level, alcohol consumption status, smoking status, self-assessed health |
| NHANES | USA; n=2927 (1453 men; 1474 women); 283 deaths | 2003–2006; 6.7 years | ActiGraph 7164 (hip); NA | National Death Index | Age, sex, ratio of family income to poverty, alcohol consumption, smoking status, energy intake, self-assessed health, physical limitations on movement, existing diagnosed medical condition (coronary heart disease, stroke, cancer, diabetes), hypertension |
| REGARDS | USA; n=7076 (3257 men; 3819 women); 477 deaths | 2003–2007; 5.7 years | Actical (hip); NA | Review of death certificates, medical records and administrative databases | Age, sex, BMI, education, race, region of residence, season accelerometer was worn, current smoking, alcohol use, diabetes, hypertension, dyslipidaemia, estimated glomerular filtration rate, atrial fibrillation, history of coronary heart disease, history of stroke, self-assessed health |
| UK Biobank | UK; n=98 819 (43 229 men; 55 590 women); 2411 deaths | 2013–2015; 5.4 years | Axivity AX3 (dominant wrist); self-report | National Health Service central registers | Age, sex, BMI, education, race, Townsend deprivation index, alcohol consumption, smoking status, self-assessed health, fruit and vegetable consumption, oily fish consumption, salt intake, red meat consumption, use of blood pressure or cholesterol medicine, physical limitations on movement, existing medical condition (cardiovascular disease, stroke, cancer), existing diagnosis of diabetes (self-reported diagnosis or use of insulin) |
| Whitehall II | UK; n=3900 (2891 men; 1009 women); 140 deaths | 2012–2013; 5.3 years | GENEActiv Original (non-dominant wrist); accelerometer | National Health Service central registers | Age, sex, occupational position, alcohol consumption, smoking status, fruit and vegetable consumption, health state (multimorbidity index made of history of diabetes, coronary heart disease, stroke, depression, cancers, arthritis, chronic obstructive pulmonary disease, dementia and Parkinson’s disease) |
| Women’s Health Study | USA; n=16 676 (all women); 503 deaths | 2011–2015; 4.3 years | ActiGraph GT3X+ (hip); NA | Review of medical records, death certificates or the National Death Index | Age, sex, income, smoking status, alcohol consumption, saturated fat intake, fibre intake, fruit and vegetable consumption, hormone therapy, family history of myocardial infarction, family history of cancer, general health, history of cardiovascular disease, history of cancer, results of cancer screen |
BMI, body mass index; NA, not applicable; NHANES, National Health and Nutrition Examination Survey.