Sleep duration, body composition and mortality: a prospective study of 156,565 Mexican adults.

CVD mortality risk was highest among individuals with high waist circumference and short sleep duration.

• HR of 7.28 (95% CI: 2.22–23.79) for high WC combined with short sleep for CVD mortality after full adjustment.
• Similarly elevated CVD mortality risks were observed for high WC combined with reference or long sleep durations.
• Short sleep was defined as <7 h/day for adults <65 years.
• Reference sleep was defined as 7–9 h/day for adults <65 years and 7–8 h/day for those ≥65 years.

Obesity was independently associated with increased CVD mortality among individuals reporting reference sleep duration.

• HR of 3.11 (95% CI: 1.28–7.55) for obesity combined with reference sleep duration for CVD mortality.
• This association was observed after full adjustment in Cox proportional hazards models.
• The study included 156,565 participants with a median follow-up of 15.5 years.

For all-cause mortality, obesity increased risk across all sleep duration categories.

• Obesity was associated with elevated all-cause mortality regardless of whether participants reported short, reference, or long sleep duration.
• High WC was also associated with elevated all-cause mortality regardless of sleep duration category.
• Participants with pre-existing conditions and early deaths were excluded from the cohort.

No significant associations were observed between the joint categories of sleep duration and body composition with respiratory mortality after full adjustment.

• Respiratory mortality analyses were conducted using the same Cox proportional hazards models.
• Full adjustment attenuated any associations that may have been present in unadjusted models.
• This null finding applied across all combinations of sleep duration and body composition categories.

Excess adiposity, particularly waist circumference, was the primary determinant of mortality risk, largely independent of sleep duration.

• Body composition was assessed by both BMI (normal weight, overweight, obesity) and waist circumference (normal or high WC).
• The prospective cohort included 156,565 Mexican adults with a median follow-up of 15.5 years.
• Cox proportional hazards models estimated HRs for combinations of sleep duration and body composition categories.
• The association between high WC and mortality persisted across short, reference, and long sleep duration categories.

The study used age-specific sleep duration reference categories to define short and long sleep.

• For adults <65 years, reference sleep was 7–9 h/day, short sleep was <7 h/day, and long sleep was >9 h/day.
• For adults ≥65 years, reference sleep was 7–8 h/day and long sleep was >8 h/day.
• Short sleep was defined as <7 h/day for both age groups.
• These age-stratified definitions were applied in all Cox proportional hazards analyses.