Sarah-Jane Paine

The Epidemiology of Morningness/Eveningness: Influence of Age, Gender, Ethnicity, and Socioeconomic Factors in Adults (30-49 Years)

The Horne and Ostberg Morningness/Eveningness Questionnaire (MEQ) is widely used to differentiate between morning and evening types, but there is very little epidemiological evidence about the distribution of MEQ chronotypes in the general population. The purpose of the present study was to simultaneously investigate the influence of demographic, socioeconomic, and work factors on the distribution of morningness/eveningness. A New Zealand version of the MEQ was mailed to 5000 New Zealand adults, ages 30 to 49 years, who were randomly selected from the electoral rolls (55.7% response rate). A total of 2526 questionnaires were included in the analyses. According to the Horne and Ostberg classification, 49.8% of the total population was classified as morning type compared to 5.6% having an evening-type preference. However, using new cutoffs for middle-aged working adults described by Taillard et al. (2004), 24.7% of the population was morning type and 26.4% was evening type. After controlling for ethnicity, gender, and socioeconomic deprivation, participants ages 30 to 34 years were more likely to be definitely evening type (odds ratio [OR] = 1.59, p < 0.05) and less likely to be morning type (moderately morning type, OR = 0.59, p < 0.01, or definitely morning type, OR = 0.59, p < 0.05) compared to those ages 45 to 49 years. Work schedules were also important predictors of chronotype, with night workers more likely to be definitely evening type (OR = 1.49, p = 0.05) and the unemployed less likely to be moderately morning type (OR = 0.64, p < 0.05) compared to other workers. Evening types were 2.5 times more likely to report that their general health was only poor or fair compared to morning types (p < 0.01). This study confirms that the original criteria of Horne and Ostberg (1976) are not useful for classifying chronotypes in a middle-aged population. The authors conclude that morningness/eveningness preference is largely independent of ethnicity, gender, and socioeconomic position, indicating that it is a stable characteristic that may be better explained by endogenous factors.

Prevalence and consequences of insomnia in New Zealand: disparities between Maori and non-Maori

Objective:

Identifying advanced and delayed sleep phase disorders in the general population: a national survey of New Zealand adults.

The aim was to estimate the prevalence of, and identify independent risk factors for, Advanced (ASPD) and Delayed Sleep Phase Disorder (DSPD) among Māori (indigenous New Zealanders) and non-Māori adults using a self-report questionnaire. The Munich Chronotype Questionnaire was mailed to a stratified sample of 9100 adults (5100 Māori and 4000 non-Māori) aged 20–59 years randomly selected from the electoral rolls (54% response rate). Different definitions for ASPD and DSPD were developed using combinations of symptoms including self-reported bed and rising times, current chronotype, and a desire to change sleep schedule. Logistic regression models were used to model the likelihood of reporting ASPD or DSPD separately after adjusting for ethnicity (Māori versus non-Māori), sex (males versus females), age (in decades), socio-economic deprivation (NZDep2006 deciles) and employment status (unemployed, night work versus employed with no night work). The prevalence of ASPD ranged from 0.25% to 7.13% whereas the prevalence of DSPD was 1.51 to 8.90% depending on the definition used. The prevalence of ASPD was higher among men and increased with age. The prevalence of DSPD was higher among those living in more deprived areas and decreased with age. After controlling for ethnicity, gender, age, socio-economic deprivation and employment status, people with ASPD were more likely to report excessive daytime sleepiness, whereas those with DSPD were more likely to report poor or fair self-rated health. Reporting ASPD and DSPD were associated with self-reported night work. In this large sleep timing survey, we found no differences in the prevalence of self-identified ASPD and DSPD between Maori and non-Maori. This has implications for the development and provision of sleep health services and strategies for managing the significant impact of work patterns on sleep.

Prevalence of abnormal sleep duration and excessive daytime sleepiness in pregnancy and the role of socio-demographic factors: comparing pregnant women with women in the general population.

OBJECTIVES To compare the prevalence of self-reported abnormal sleep duration and excessive daytime sleepiness in pregnancy among Māori (indigenous New Zealanders) and non-Māori women versus the general population, and to examine the influence of socio-demographic factors. METHODS Self-reported total sleep time (TST) in 24-hrs, Epworth Sleepiness Scale scores and socio-demographic information were obtained from nullipara and multipara women aged 20-46 yrs at 35-37 weeks pregnant (358 Māori and 717 non-Māori), and women in the general population (381 Māori and 577 non-Māori). RESULTS After controlling for ethnicity, age, socio-economic status, and employment status, pregnant women average 30 min less TST than women in the general population. The distribution of TST was also greater in pregnant women, who were 3 times more likely to be short sleepers (≤6 h) and 1.9 times more likely to be long sleepers (>9 h). In addition, pregnant women were 1.8 times more likely to report excessive daytime sleepiness (EDS). Pregnant women >30 years of age experienced greater age-related declines in TST. Identifying as Māori, being unemployed, and working at night increased the likelihood of reporting abnormal sleep duration across all women population in this study. EDS also more likely occurred among Māori women and women who worked at night. CONCLUSIONS Pregnancy increases the prevalence of abnormal sleep duration and EDS, which are also higher among Māori than non-Māori women and those who do night work. Health professionals responsible for the care of pregnant women need to be well-educated about the importance of sleep and discuss sleep issues with the women they care for.

Self-reported sleep in late pregnancy in relation to birth size and fetal distress: the E Moe, Māmā prospective cohort study.

Objectives To explore associations between features of sleep during pregnancy and adverse outcomes for the infant. Setting E Moe, Māmā is a cohort study in Aotearoa/New Zealand that investigates self-reported sleep and maternal health in late pregnancy and the postpartum period. Participants Women (N=633; 194 Māori) reported detailed information on their sleep duration, quality, disturbances, disorders (snoring, breathing pauses, twitching legs, restless legs) and daytime sleepiness between 35 and 37 weeks gestation. Outcome measures Birthweight and fetal distress during labour were extracted from medical records. Associations between each sleep variable and small or large for gestational age (SGA/LGA) using customised birthweight centile or fetal distress were estimated using multinomial/logistic regression, controlling for potential confounders. Secondary analyses considered differences in associations between Māori and non-Māori women. Results There was some indication that breathing pauses (a measure of sleep apnoea) were associated with both SGA (OR 2.8, 95% CI 0.9 to 9.0, p=0.08) and LGA (OR 2.0, 95% CI 0.7 to 5.7, p=0.20), with the association for LGA being stronger when only pregnancy-onset breathing pauses were considered (OR 3.5, 95% CI 1.3 to 9.6, p=0.01). There was also some evidence that pregnancy-onset leg twitching (OR 3.3, 95% CI 1.1 to 10.0, p=0.03) and frequent sleep disturbance due to feeling too hot or too cold (OR 1.7, 95% CI 0.9 to 3.6, p=0.13) were associated with higher risk of fetal distress. Other sleep measures, including snoring, were not associated with SGA, LGA or fetal distress. Many of the associations we observed were considerably stronger in Māori compared with non-Māori women. Conclusions We did not find evidence of previously reported associations between snoring and SGA. Our findings tentatively suggest that self-reported breathing pauses and leg twitching in late pregnancy are associated with infant outcomes, and highlight ethnic inequalities.

Sleep, Sleepiness, and Sleep Disorders: Principles for Examining Differences by Ethnicity

Despite the growing recognition of the causes and consequences of ethnic disparities in other aspects of health, very little is known about disparities in sleep between different ethnic groups. Rigorous epidemiological studies can provide valuable information about the prevalence and consequences of sleepiness and sleep disorders and the profile of risk factors in different groups. This article describes a methodological approach that aims to better understand and help eliminate ethnic inequities in sleep health.

Differences in circadian phase and weekday/weekend sleep patterns in a sample of middle-aged morning types and evening types.

ABSTRACT Factors contributing to sleep timing and sleep restriction in daily life include chronotype and less flexibility in times available for sleep on scheduled days versus free days. There is some evidence that these two factors interact, with morning types and evening types reporting similar sleep need, but evening types being more likely to accumulate a sleep debt during the week and to have greater sleep extension on weekend nights. The aim of the present study was to evaluate the independent contributions of circadian phase and weekend-to-weekday variability to sleep timing in daily life. The study included 14 morning types and 14 evening types recruited from a community-based sample of New Zealand adults (mean age 41.1 ± 4.7 years). On days 1–15, the participants followed their usual routines in their own homes and daily sleep start, midpoint and end times were determined by actigraphy and sleep diaries. Days 16–17 involved a 17 h modified constant routine protocol in the laboratory (17:00 to 10:00, <20 lux) with half-hourly saliva samples assayed for melatonin. Mixed model ANCOVAs for repeated measures were used to investigate the independent relationships between sleep start and end times (separate models) and age (30–39 years versus 40–49 years), circadian phase [time of the dim light melatonin onset (DLMO)] and weekday/weekend schedules (Sunday–Thursday nights versus Friday–Saturday nights). As expected on weekdays, evening types had later sleep start times (mean = 23:47 versus 22:37, p < .0001) and end times (mean = 07:14 versus 05:56, p < .0001) than morning types. Similarly on weekend days, evening types had later sleep start times (mean = 00:14 versus 23:07, p = .0032) and end times (mean = 08:56 versus 07:04, p < .0001) than morning types. Evening types also had later DLMO (22:06 versus 20:46, p = .0002) than morning types (mean difference = 80.4 min, SE = 18.6 min). The ANCOVA models found that later sleep start times were associated with later DLMO (p = .0172) and weekend-to-weekday sleep timing variability (p < .0001), after controlling for age, while later sleep end times were associated with later DLMO (p = .0038), younger age (p = .0190) and weekend days (p < .0001). Sleep end times showed stronger association with DLMO (for every 30 min delay in DLMO, estimated mean sleep end time occurred 14.0 min later versus 10.19 min later for sleep start times). Sleep end times also showed greater delays on weekends versus weekdays (estimated mean delay for sleep end time = 84 min, for sleep start time = 28 min). Comparing morning types and evening types, the estimated contributions of the DLMO to the mean observed differences in sleep timing were on weekdays, 39% for sleep start times and 49% for sleep end times; and on weekends, 41% for sleep start times and 34% of sleep end times. We conclude that differences in sleep timing between morning types and evening types were much greater than would be predicted on the basis of the independent contribution of the difference in DLMO on both weekdays and weekend days. The timing of sleep in daily life involves complex interactions between physiological and psychosocial factors, which may be moderated by age in adults aged 30–49 years.

The prevalence of symptoms of depression and anxiety, and the level of life stress and worry in New Zealand Māori and non-Māori women in late pregnancy

Objective: To describe the prevalence of symptoms of depression and anxiety, and the level of life stress and worry in late pregnancy for Māori and non-Māori women. Methods: In late pregnancy, women completed a questionnaire recording their prior history of mood disorders; self-reported current depressive symptoms (⩾13 on the Edinburgh Postnatal Depression Scale), current anxiety symptoms (⩾6 on the anxiety items from the Edinburgh Postnatal Depression Scale), significant life stress (⩾2 items on life stress scale) and dysfunctional worry (>12 on the Brief Measure of Worry Scale). Results: Data were obtained from 406 Māori women (mean age = 27.6 years, standard deviation=6.3 years) and 738 non-Māori women (mean age = 31.6 years, standard deviation=5.3 years). Depressive symptoms (22% vs 15%), anxiety symptoms (25% vs 20%), significant life stress (55% vs 30%) and a period of poor mood during the current pregnancy (18% vs 14%) were more prevalent for Māori than non-Maori women. Less than 50% of women who had experienced ⩾2 weeks of poor mood during the current pregnancy had sought help. Being young was an independent risk factor for depressive symptoms, significant life stress and dysfunctional worry. A prior history of depression was also consistently associated with a greater risk of negative affect in pregnancy. Conclusion: Antenatal mental health requires at least as much attention and resourcing as mental health in the postpartum period. Services need to specifically target Māori women, young women and women with a prior history of depression.

Caregiver experiences of racism and child healthcare utilisation: cross-sectional analysis from New Zealand

Objectives Children’s exposure to racism via caregiver experience (vicarious racism) is associated with poorer health and development. However, the relationship with child healthcare utilisation is unknown. We aimed to investigate (1) the prevalence of vicarious racism by child ethnicity; (2) the association between caregiver experiences of racism and child healthcare utilisation; and (3) the contribution of caregiver socioeconomic position and psychological distress to this association. Design Cross-sectional analysis of two instances of the New Zealand Health Survey (2006/2007: n=4535 child–primary caregiver dyads; 2011/2012: n=4420 dyads). Main outcome measures Children’s unmet need for healthcare, reporting no usual medical centre and caregiver-reported dissatisfaction with their child’s medical centre. Results The prevalence of reporting ‘any’ experience of racism was higher among caregivers of indigenous Māori and Asian children (30.0% for both groups in 2006/2007) compared with European/Other children (14.4% in 2006/2007). Vicarious racism was independently associated with unmet need for child’s healthcare (OR=2.30, 95% CI 1.65 to 3.20) and dissatisfaction with their child’s medical centre (OR=2.00, 95% CI 1.26 to 3.16). Importantly, there was a dose–response relationship between the number of reported experiences of racism and child healthcare utilisation (eg, unmet need: 1 report of racism, OR=1.89, 95% CI 1.34 to 2.67; 2+ reports of racism, OR=3.06, 95% CI 1.27 to 7.37). Adjustment for caregiver psychological distress attenuated the association between caregiver experiences of racism and child healthcare utilisation. Conclusions Vicarious racism is a serious health problem in New Zealand disproportionately affecting Māori and Asian children and significantly impacting children’s healthcare utilisation. Tackling racism may be an important means of improving inequities in child healthcare utilisation.

Estimating the economic costs of ethnic health inequities: protocol for a prevalence-based cost-of-illness study in New Zealand (2003–2014)

Introduction There is significant international interest in the economic impacts of persistent inequities in morbidity and mortality. However, very few studies have quantified the costs associated with unfair and preventable ethnic/racial inequities in health. The proposed study will investigate inequities in health between the indigenous Māori and non-Māori adult population in New Zealand (15 years and older) and estimate the economic costs associated with these differences. Methods and analysis The study will use national collections data that is held by government agencies in New Zealand including hospitalisations, mortality, outpatient consultations, laboratory and pharmaceutical claims, and accident compensation claims. Epidemiological methods will be used to calculate prevalences for Māori and non-Māori, by age-group, gender and socioeconomic deprivation (New Zealand Deprivation Index) where possible. Rates of ‘potentially avoidable’ hospitalisations and mortality as well as ‘excess or under’ utilisation of healthcare will be calculated as the difference between the actual rate and that expected if Māori were to have the same rates as non-Māori. A prevalence-based cost-of-illness approach will be used to estimate health inequities and the costs associated with treatment, as well as other financial and non-financial costs (such as years of life lost) over the person’s lifetime. Ethics and dissemination This analysis has been approved by the University of Auckland Human Participants Research Committee (Ref: 018621). Dissemination of findings will occur via published peer-reviewed articles, presentations to academic, policy and community-based stakeholder groups and via social media.