JECH Online First, published on August 7, 2015 as 10.1136/jech-2015-205583 Research report
Student loans and racial disparities in self-reported sleep duration: evidence from a nationally representative sample of US young adults Katrina M Walsemann,1 Jennifer A Ailshire,2 Gilbert C Gee3 1
Department of Health Promotion, Education, and Behavior, University of South Carolina, Arnold School of Public Health, Columbia, South Carolina, USA 2 University of Southern California, Davis School of Gerontology, Los Angeles, California, USA 3 Department of Community Health Sciences, University of California, Los Angeles, Fielding School of Public Health, Los Angeles, California, USA Correspondence to Dr Katrina M Walsemann, Department of Health Promotion, Education, and Behavior, University of South Carolina, Arnold School of Public Health, 915 Greene Street, Room 529, Columbia, SC 29208, USA; [email protected] Received 2 February 2015 Revised 24 May 2015 Accepted 19 July 2015
ABSTRACT Background Student loans are the second largest source of personal debt in the USA and may represent an important source of financial strain for many young adults. Little attention has been paid to whether debt is associated with sleep duration, an important healthpromoting behaviour. We determine if student loans are associated with sleep duration. Since black young adults are more likely to have student debt and sleep less, we also consider whether this association varies by race. Methods Data come from the US National Longitudinal Survey of Youth 1997. The main analytic sample includes 4714 respondents who were ever enrolled in college and who reported on sleep duration in 2010. Most respondents had completed their college education by 2010, when respondents were 25 to 31 years old. Multivariable linear regression models assessed the cross-sectional association between student loans accumulated over the course of college and sleep duration in 2010, as well as between student debt at age 25 and sleep duration in 2010. Results Black young adults with greater amounts of student loans or more student debt reported shorter sleep duration, controlling for occupation, hours worked, household income, parental net worth, marital status, number of children in the household and other sociodemographic and health indicators. There was no association between student loans or debt with sleep for white or latino adults and other racial/ethnic groups. Conclusions Student loans may contribute to racial inequities in sleep duration. Our findings also suggest that the student debt crisis may have important implications for individuals’ sleep, specifically and public health, more broadly.
likely to lie awake at night, either due to difficulty falling asleep or because they wake in the night and cannot fall back to sleep, and thus, have shorter sleep.10 11 13 Although these studies demonstrate a link between financial strain and disrupted sleep, it is still unknown if debt is directly associated with sleep, in general or total sleep duration, specifically. We know, however, that psychosocial stressors strongly affect sleep,13–17 and that student debt may be an important psychosocial stressor that could ultimately impact the amount of sleep individuals experience. Since student loans may be a major source of financial stress for many young adults,18 19 we hypothesise that borrowing greater amounts of student loans will be associated with shorter sleep duration. We further investigate differences by race/ ethnicity. Compared to white individuals, black individuals report sleeping roughly 30–45 min less per night20 and are twice as likely to report sleeping five or fewer hours per night.21 Previous research finds that black individuals have a greater burden of daily hassles and stressors, including more financial strain, which can contribute to their shorter sleep duration.13 17 Further, black individuals generally have smaller economic22 23 and health returns23 24 to education compared with white individuals. For example, in 2008–2010, black male college graduates earned 28% less than their white counterparts.22 Black graduates may, therefore, experience greater financial strain as a result of student debt compared with white graduates, even at equivalent levels of student debt. Thus, we also hypothesise that the negative association between student loans and sleep duration will be stronger among black graduates than white graduates.
INTRODUCTION
To cite: Walsemann KM, Ailshire JA, Gee GC. J Epidemiol Community Health Published Online First: [please include Day Month Year] doi:10.1136/jech2015-205583
One of the largest sources of personal debt in the USA originates from student loans, amounting to over $1 trillion dollars.1 The USA has some of the least favourable terms for repayment or forgiveness of student loan debt (eg, shorter grace-period for repayment, stringent default rules and few options for loan forgiveness).2 As such, student debt may represent an important financial stressor for borrowers. Debt has been linked to greater stress and poorer mental health,3–6 but there has been little attention to how debt affects sleep, an important health-promoting behaviour.7–9 Financial strain and the stress, worry and anxiety that accompany it can disrupt sleep, which may result in shorter sleep duration.10–12 Prior research has found that individuals experiencing persistent financial strain and economic difficulties are more
METHODS Data We analysed data from the National Longitudinal Survey of Youth 1997 (NLSY97), a nationally representative sample of 8984 individuals born between 1980 and 1984.25 Baseline interviews were conducted in 1997, with annual follow-up interviews ongoing. Our analyses include data through 2010, the year when sleep was measured. The retention rate over the 13-year period was 80%. This study was considered exempt by the Institutional Review Board at the University of South Carolina and conforms to the principles of the Declaration of Helsinki. We constructed two analytical samples to correspond with our independent variables of student borrowing and student debt. Our main analytic
Walsemann KM, et al. J Epidemiol Community Health 2015;0:1–7. doi:10.1136/jech-2015-205583
Copyright Article author (or their employer) 2015. Produced by BMJ Publishing Group Ltd under licence.
1
Research report sample (hereafter referred to as the full sample) consisted of any respondent who had ever enrolled in college by 2010 (n=5546). We excluded an additional 832 respondents who were not interviewed in 2010 or had missing data on sleep, resulting in a final analytic sample of 4714. Supplemental analysis indicated that non-response was more common among older respondents, immigrants and those raised in the wealthiest families and was less common among black individuals, hispanic individuals and transfer students. Our second analytic sample (hereafter referred to as the subsample) consisted of any respondent who had ever enrolled in college by the year they reported on student debt (at or around age 25), resulting in an analytical sample of 4459. Although respondents were asked about student debt when they were age 25 and 30, only 18% of respondents turned 30 by 2010. Thus, we only include information about debt at age 25.
Measures Dependent variable: sleep duration
Respondents were asked “On a typical weeknight, how many hours of sleep do you usually get?” Responses ranged from 0 to 24 h and were reported in 1 h increments. This yielded a normally distributed, continuous variable.
Independent variables: student loans and student debt Student loans were measured by asking students how much they borrowed in government subsidised loans or other types of loans (excluding loans from relatives and friends) for each and every semester between 1997 and 2010. We then summed these amounts to arrive at the total amount of student loans borrowed during this period. We top-coded student loans at the 95th centile. Student debt was measured by asking how much respondents owed on student loans at age 25. We top-coded student debt at the 95th centile. We also included a quadratic indicator of student debt, since the association between student debt and sleep duration was non-linear.
Covariates We included demographic and socioeconomic indicators that might be associated with student loans/debt and sleep duration. All covariates were assessed in 2010 unless otherwise noted. Enrollment history refers to the type of colleges respondents attended and was categorised as: (1) attended a 2-year college only; (2) attended both a 2-year and 4-year college; or (3) attended a 4-year college only. The latter two categories also include those who attended graduate school. Last year enrolled in college uses enrolment data to adjust for variation in time since last year of enrolment. Values ranged from 1998 to 2010. For the subsample, this measure was created based on the year the respondent reported on student debt. Educational attainment was measured using the highest degree attained, which was categorised as less than a Bachelor’s degree versus a Bachelor’s degree or higher. More refined categories of degree attainment yielded similar results. Number of hours worked, on average, in the prior year was categorised as 0 h, 1–39 h, and 40 or more hours. Total number of jobs the respondent held was measured as a count from 0 to 6. Occupational status was assessed based on the respondents’ current or most recent job using the 2002 Census Occupational Codes, and categorised as (1) professional or managerial; (2) sales, service or technician; (3) labour, production or farmer; (4) active military; and (5) not working. Self-reported household income was categorised as 0–49th centile, 50th–74th centile and 75th centile and over. 2
Other financial debt (ie, credit cards, car loans, debt owed to businesses or to relatives) was self-reported by respondents. The variable excludes student debt. Inclusion of both a dichotomous indicator of any debt and a continuous measure of total debt in regression models showed that having any debt was related to sleep duration, but the amount of debt was not. Thus, we only include the dichotomous indicator in the analysis we present. Marital status was categorised as (1) never married; (2) married; or (3) divorced, separated or widowed. Number of children under age 18 living in the household was included as a continuous indicator ranging from 0 to 9. We also include region of the USA (south, north, west or outside the USA), urbanicity (urban, rural or undetermined), self-reported race/ethnicity (non-Hispanic White, non-Hispanic Black, Latino and other), nativity (born a US citizen or not), gender, age and pregnancy status ( pregnant vs not). For the subsample, regression models also include an indicator for the year they answered questions about student debt. To partially control for selection into college, parents’ net worth reported by respondents’ parents in 1997 was calculated as the amount of debt subtracted from assets (home equity, bonds/CDs/stocks, life insurance policies, pension and retirement savings, car values, etc) and categorised as negative net worth (
Student loans and racial disparities in self-reported sleep duration: evidence from a nationally representative sample of US young adults Katrina M Walsemann,1 Jennifer A Ailshire,2 Gilbert C Gee3 1
Department of Health Promotion, Education, and Behavior, University of South Carolina, Arnold School of Public Health, Columbia, South Carolina, USA 2 University of Southern California, Davis School of Gerontology, Los Angeles, California, USA 3 Department of Community Health Sciences, University of California, Los Angeles, Fielding School of Public Health, Los Angeles, California, USA Correspondence to Dr Katrina M Walsemann, Department of Health Promotion, Education, and Behavior, University of South Carolina, Arnold School of Public Health, 915 Greene Street, Room 529, Columbia, SC 29208, USA; [email protected] Received 2 February 2015 Revised 24 May 2015 Accepted 19 July 2015
ABSTRACT Background Student loans are the second largest source of personal debt in the USA and may represent an important source of financial strain for many young adults. Little attention has been paid to whether debt is associated with sleep duration, an important healthpromoting behaviour. We determine if student loans are associated with sleep duration. Since black young adults are more likely to have student debt and sleep less, we also consider whether this association varies by race. Methods Data come from the US National Longitudinal Survey of Youth 1997. The main analytic sample includes 4714 respondents who were ever enrolled in college and who reported on sleep duration in 2010. Most respondents had completed their college education by 2010, when respondents were 25 to 31 years old. Multivariable linear regression models assessed the cross-sectional association between student loans accumulated over the course of college and sleep duration in 2010, as well as between student debt at age 25 and sleep duration in 2010. Results Black young adults with greater amounts of student loans or more student debt reported shorter sleep duration, controlling for occupation, hours worked, household income, parental net worth, marital status, number of children in the household and other sociodemographic and health indicators. There was no association between student loans or debt with sleep for white or latino adults and other racial/ethnic groups. Conclusions Student loans may contribute to racial inequities in sleep duration. Our findings also suggest that the student debt crisis may have important implications for individuals’ sleep, specifically and public health, more broadly.
likely to lie awake at night, either due to difficulty falling asleep or because they wake in the night and cannot fall back to sleep, and thus, have shorter sleep.10 11 13 Although these studies demonstrate a link between financial strain and disrupted sleep, it is still unknown if debt is directly associated with sleep, in general or total sleep duration, specifically. We know, however, that psychosocial stressors strongly affect sleep,13–17 and that student debt may be an important psychosocial stressor that could ultimately impact the amount of sleep individuals experience. Since student loans may be a major source of financial stress for many young adults,18 19 we hypothesise that borrowing greater amounts of student loans will be associated with shorter sleep duration. We further investigate differences by race/ ethnicity. Compared to white individuals, black individuals report sleeping roughly 30–45 min less per night20 and are twice as likely to report sleeping five or fewer hours per night.21 Previous research finds that black individuals have a greater burden of daily hassles and stressors, including more financial strain, which can contribute to their shorter sleep duration.13 17 Further, black individuals generally have smaller economic22 23 and health returns23 24 to education compared with white individuals. For example, in 2008–2010, black male college graduates earned 28% less than their white counterparts.22 Black graduates may, therefore, experience greater financial strain as a result of student debt compared with white graduates, even at equivalent levels of student debt. Thus, we also hypothesise that the negative association between student loans and sleep duration will be stronger among black graduates than white graduates.
INTRODUCTION
To cite: Walsemann KM, Ailshire JA, Gee GC. J Epidemiol Community Health Published Online First: [please include Day Month Year] doi:10.1136/jech2015-205583
One of the largest sources of personal debt in the USA originates from student loans, amounting to over $1 trillion dollars.1 The USA has some of the least favourable terms for repayment or forgiveness of student loan debt (eg, shorter grace-period for repayment, stringent default rules and few options for loan forgiveness).2 As such, student debt may represent an important financial stressor for borrowers. Debt has been linked to greater stress and poorer mental health,3–6 but there has been little attention to how debt affects sleep, an important health-promoting behaviour.7–9 Financial strain and the stress, worry and anxiety that accompany it can disrupt sleep, which may result in shorter sleep duration.10–12 Prior research has found that individuals experiencing persistent financial strain and economic difficulties are more
METHODS Data We analysed data from the National Longitudinal Survey of Youth 1997 (NLSY97), a nationally representative sample of 8984 individuals born between 1980 and 1984.25 Baseline interviews were conducted in 1997, with annual follow-up interviews ongoing. Our analyses include data through 2010, the year when sleep was measured. The retention rate over the 13-year period was 80%. This study was considered exempt by the Institutional Review Board at the University of South Carolina and conforms to the principles of the Declaration of Helsinki. We constructed two analytical samples to correspond with our independent variables of student borrowing and student debt. Our main analytic
Walsemann KM, et al. J Epidemiol Community Health 2015;0:1–7. doi:10.1136/jech-2015-205583
Copyright Article author (or their employer) 2015. Produced by BMJ Publishing Group Ltd under licence.
1
Research report sample (hereafter referred to as the full sample) consisted of any respondent who had ever enrolled in college by 2010 (n=5546). We excluded an additional 832 respondents who were not interviewed in 2010 or had missing data on sleep, resulting in a final analytic sample of 4714. Supplemental analysis indicated that non-response was more common among older respondents, immigrants and those raised in the wealthiest families and was less common among black individuals, hispanic individuals and transfer students. Our second analytic sample (hereafter referred to as the subsample) consisted of any respondent who had ever enrolled in college by the year they reported on student debt (at or around age 25), resulting in an analytical sample of 4459. Although respondents were asked about student debt when they were age 25 and 30, only 18% of respondents turned 30 by 2010. Thus, we only include information about debt at age 25.
Measures Dependent variable: sleep duration
Respondents were asked “On a typical weeknight, how many hours of sleep do you usually get?” Responses ranged from 0 to 24 h and were reported in 1 h increments. This yielded a normally distributed, continuous variable.
Independent variables: student loans and student debt Student loans were measured by asking students how much they borrowed in government subsidised loans or other types of loans (excluding loans from relatives and friends) for each and every semester between 1997 and 2010. We then summed these amounts to arrive at the total amount of student loans borrowed during this period. We top-coded student loans at the 95th centile. Student debt was measured by asking how much respondents owed on student loans at age 25. We top-coded student debt at the 95th centile. We also included a quadratic indicator of student debt, since the association between student debt and sleep duration was non-linear.
Covariates We included demographic and socioeconomic indicators that might be associated with student loans/debt and sleep duration. All covariates were assessed in 2010 unless otherwise noted. Enrollment history refers to the type of colleges respondents attended and was categorised as: (1) attended a 2-year college only; (2) attended both a 2-year and 4-year college; or (3) attended a 4-year college only. The latter two categories also include those who attended graduate school. Last year enrolled in college uses enrolment data to adjust for variation in time since last year of enrolment. Values ranged from 1998 to 2010. For the subsample, this measure was created based on the year the respondent reported on student debt. Educational attainment was measured using the highest degree attained, which was categorised as less than a Bachelor’s degree versus a Bachelor’s degree or higher. More refined categories of degree attainment yielded similar results. Number of hours worked, on average, in the prior year was categorised as 0 h, 1–39 h, and 40 or more hours. Total number of jobs the respondent held was measured as a count from 0 to 6. Occupational status was assessed based on the respondents’ current or most recent job using the 2002 Census Occupational Codes, and categorised as (1) professional or managerial; (2) sales, service or technician; (3) labour, production or farmer; (4) active military; and (5) not working. Self-reported household income was categorised as 0–49th centile, 50th–74th centile and 75th centile and over. 2
Other financial debt (ie, credit cards, car loans, debt owed to businesses or to relatives) was self-reported by respondents. The variable excludes student debt. Inclusion of both a dichotomous indicator of any debt and a continuous measure of total debt in regression models showed that having any debt was related to sleep duration, but the amount of debt was not. Thus, we only include the dichotomous indicator in the analysis we present. Marital status was categorised as (1) never married; (2) married; or (3) divorced, separated or widowed. Number of children under age 18 living in the household was included as a continuous indicator ranging from 0 to 9. We also include region of the USA (south, north, west or outside the USA), urbanicity (urban, rural or undetermined), self-reported race/ethnicity (non-Hispanic White, non-Hispanic Black, Latino and other), nativity (born a US citizen or not), gender, age and pregnancy status ( pregnant vs not). For the subsample, regression models also include an indicator for the year they answered questions about student debt. To partially control for selection into college, parents’ net worth reported by respondents’ parents in 1997 was calculated as the amount of debt subtracted from assets (home equity, bonds/CDs/stocks, life insurance policies, pension and retirement savings, car values, etc) and categorised as negative net worth (
