Independent Effects of Sleep Duration and Body Mass Index on the Risk of a Work-Related Injury: Evidence From the US National Health Interview Survey (2004–2010)

Abstract

Fatigue has been linked to adverse safety outcomes, and poor quality or decreased sleep has been associated with obesity (higher body mass index, BMI). Additionally, higher BMI is related to an increased risk for injury; however, it is unclear whether BMI modifies the effect of short sleep or has an independent effect on work-related injury risk. To answer this question, the authors examined the risk of a work-related injury as a function of total daily sleep time and BMI using the US National Health Interview Survey (NHIS). The NHIS is an in-person household survey using a multistage, stratified, clustered sample design representing the US civilian population. Data were pooled for the 7-yr survey period from 2004 to 2010 for 101 891 "employed" adult subjects (51.7%; 41.1 ± yrs of age [mean ± SEM]) with data on both sleep and BMI. Weighted annualized work-related injury rates were estimated across a priori defined categories of BMI: healthy weight (BMI: <25), overweight (BMI: 25-29.99), and obese (BMI: ≥30) and also categories of usual daily sleep duration: <6, 6-6.99, 7-7.99, 8-8.99, and ≥9 h. To account for the complex sampling design, including stratification, clustering, and unequal weighting, weighted multiple logistic regression was used to estimate the risk of a work-related injury. The initial model examined the interaction among daily sleep duration and BMI, controlling for weekly working hours, age, sex, race/ethnicity, education, type of pay, industry, and occupation. No significant interaction was found between usual daily sleep duration and BMI (p = .72); thus, the interaction term of the final logistic model included these two variables as independent predictors of injury, along with the aforementioned covariates. Statistically significant covariates (p ≤ .05) included age, sex, weekly work hours, occupation, and if the worker was paid hourly. The lowest categories of usual sleep duration (<6 and 6-6.9 h) showed significantly (p ≤ .05) elevated injury risks than the referent category (7-8 h sleep), whereas sleeping >7-8 h did not significantly elevate risk. The adjusted injury risk odds ratio (OR) for a worker with a usual daily sleep of <6 h was 1.86 (95% confidence interval [CI]: 1.37-2.52), and for 6-6.9 h it was 1.46 (95% CI: 1.18-1.80). With regards to BMI, the adjusted injury risk OR comparing workers who were obese (BMI: ≥30) to healthy weight workers (BMI: <25) was 1.34 (95% CI: 1.09-1.66), whereas the risk in comparing overweight workers (BMI: 25-29.99) to healthy weight risk was elevated, but not statistically significant (OR = 1.08; 95% CI: .88-1.33). These results from a large representative sample of US workers suggest increase in work-related injury risk for reduced sleep regardless of worker's body mass. However, being an overweight worker also increases work-injury risk regardless of usual daily sleep duration. The independent additive risk of these factors on work-related injury suggests a substantial, but at least partially preventable, risk.

Association between sleep pattern and body mass index among undergraduate health colleges’ students at Qassim University, Saudi Arabia

“…One study showed that short self-reported sleep duration is linked to elevated BMI and may change appetite hormones [47] and in addition, a very recent study by Peltzer and Pengpid [59] confirmed an association between short sleep duration and increased BMI. In 2010, Lombardi et al [45] reported that poor quality or decreased sleep has been associated with obesity, this study's assumption supported by our observed finding; frequency of poor sleep was higher in over weight and obese participants as rate of 45.8% from all participants but still no statistically significant association was seen between poor sleep and body mass index of participants within the PSQI scoring. Otherwise, sleep quality and duration to fall into sleep in relation with BMI-as a single question-found nursing students only had statically association between sleep quality/duration to fall in sleep and BMI.…”

“…[44] In 2010, Lombardi et al [45] mentioned that fatigue has been linked to adverse safety outcomes, and poor quality or decreased sleep has been associated with obesity. Moreover, objective measures of sleep showed that this pattern of disordered eating occurs during non-REM sleep and is associated with low sleep efficiency.…”

Does obesity contribute to non-fatal occupational injury? Evidence from the National Longitudinal Survey of Youth

“…A significant proportion of populations in developed countries in Europe and North America are obese (7), and obesity has also become more common in the developing world (8). Obesity is known to increase the risk of cardiovascular diseases and diabetes (8); lately obesity has been suggested as a risk factor for occupational injury (9)(10)(11)(12)5). Despite such observations, obesity's contribution to occupational injury risk remains far from clear in epidemiological literature.…”

Economic Conditions at School Leaving and Sleep Patterns Across the Life Course

“…Sleep deprivation and poor-quality sleep is linked with lower productivity in the labor market (Williamson and Feyer 2000;Baldwin and Daugherty 2004;Landrigan et al 2004;Daley et al 2009;Lombardi et al 2012), increased health-care use (Redline and Newman 2002;Daley et al 2009), and increased risk of traffic accidents (Monk 1980;Hicks, Lindseth, and Hawkins 1983;Knipling and Wang 1994;Powell et al 2001). Sleep is believed to be linked with these outcomes through its impact on cognitive performance, decision-making abilities, memory, mood, reaction times, etc.…”