Habitual Snoring and Depressive Symptoms During Pregnancy
Habitual Snoring and Depressive Symptoms During Pregnancy
These data comprise a retrospective review of medical records of women who had been previously screened for SDB symptoms during pregnancy between July 2007 and July 2010 and who had also been clinically screened for depressive symptoms. Clinical screening for depressive symptoms, using the Edinburgh Postnatal Depression Scale (EPDS), is part of routine clinical care at our institution. The study was approved by the University of Michigan Institutional Review Board. Since this study was a retrospective review of data already prospectively obtained, informed consent was not obtained from subjects.
Sleep data retrospectively extracted for the current study were originally obtained from women during the 3 trimester of pregnancy. This included the presence of habitual snoring and "stopped breathing/gasped for air" at night. Habitual snoring had been defined as snoring either "3–4 times per week" or "almost everyday". The timing of snoring had also been noted which allowed classification into controls (non-snorers both before pregnancy and during the pregnancy through the 3 trimester) and chronic snorers (snorers prior to pregnancy or those who started habitually snoring before 28 weeks' gestation). In addition to SDB symptoms, self-reported bed times and wake times had been also obtained and sleep duration calculated. In the current study short sleep duration was defined as self-reported sleep duration of ≤6 hours per night and long sleep duration was defined as self-reported sleep duration ≥10 hours per night. Sleep quality and daytime function had been assessed using the 21-item self-report General Sleep Disturbance Scale (GSDS). Women had been asked to provide the frequency of specific sleep complaints from 0 (not at all) to 7 (every day). The GSDS comprises several subscale domains including sleep quality and daytime function. Consistent with the Diagnostic and Statistical Manual of Mental Disorders criteria for insomnia (American Psychiatric Association 1994), clinically significant sleep disturbance was identified by a mean domain score of 3 or more.
The EPDS is a 10-item self-report, depressive symptoms screening questionnaire that has been validated for the identification of depressive symptoms over the previous 7 days in pregnant and postpartum women. Scores range from 0 to 30; higher scores indicate more depressive symptoms. A threshold of 9/10 has been suggested as an appropriate threshold for routine use in primary care to identify women with depressed mood. Thus, in the present study women with a score ≥10 were classified as having depressive symptoms. However, it has also been suggested that a higher threshold (e.g. EPDS ≥ 15) may be more appropriate for pregnant women due to the heightened anxiety during gestation; analyses were therefore repeated for this subgroup.
Other variables extracted from medical records included demographics (age, race, educational level, marital status), height, weight, and parity. Obesity was defined as a pre-pregnancy Body Mass Index (BMI) ≥30 kg/m. Data were also collected on previous history of depressive disorder, current diagnosis of depressive disorder, previous or family history of gestational hypertension or pre-eclampsia, smoking status, a diagnosis of chronic hypertension, gestational hypertension, pre-eclampsia, or gestational diabetes. The latter diagnoses were obtained from medical coding using the International Classification of Diseases, 9th edition (ICD-9) and were verified using medical records.
All data obtained were double-entered into a database and analyzed with SPSS (version 19.0, IBM). Histograms, box-plots, and descriptive methods were used to examine data for errors and outliers. Between-group comparisons of continuous variables (EPDS score, maternal age, BMI, and gestational age) were conducted with t-tests (snoring vs. no snoring). Dichotomized variables (positive screen for depressive symptoms vs. negative screen for depressive symptoms) were compared with Chi Square tests. Correlations between continuous variables (EPDS score, sleep duration, sleep quality score, and daytime function score) were conducted using Pearson's Correlation Coefficient. Logistic regression was used to determine associations between snoring and depressive symptoms after adjusting for potential covariates where appropriate (including maternal race, pre-pregnancy obesity, parity, educational level, presence of a partner, pre-eclampsia, diabetes, sleep quality score). Odds ratios (OR) and 95% Confidence Intervals (CI) were calculated. A p-value <0.05 was considered statistically significant.
Methods
Participants
These data comprise a retrospective review of medical records of women who had been previously screened for SDB symptoms during pregnancy between July 2007 and July 2010 and who had also been clinically screened for depressive symptoms. Clinical screening for depressive symptoms, using the Edinburgh Postnatal Depression Scale (EPDS), is part of routine clinical care at our institution. The study was approved by the University of Michigan Institutional Review Board. Since this study was a retrospective review of data already prospectively obtained, informed consent was not obtained from subjects.
Data Collection
Sleep data retrospectively extracted for the current study were originally obtained from women during the 3 trimester of pregnancy. This included the presence of habitual snoring and "stopped breathing/gasped for air" at night. Habitual snoring had been defined as snoring either "3–4 times per week" or "almost everyday". The timing of snoring had also been noted which allowed classification into controls (non-snorers both before pregnancy and during the pregnancy through the 3 trimester) and chronic snorers (snorers prior to pregnancy or those who started habitually snoring before 28 weeks' gestation). In addition to SDB symptoms, self-reported bed times and wake times had been also obtained and sleep duration calculated. In the current study short sleep duration was defined as self-reported sleep duration of ≤6 hours per night and long sleep duration was defined as self-reported sleep duration ≥10 hours per night. Sleep quality and daytime function had been assessed using the 21-item self-report General Sleep Disturbance Scale (GSDS). Women had been asked to provide the frequency of specific sleep complaints from 0 (not at all) to 7 (every day). The GSDS comprises several subscale domains including sleep quality and daytime function. Consistent with the Diagnostic and Statistical Manual of Mental Disorders criteria for insomnia (American Psychiatric Association 1994), clinically significant sleep disturbance was identified by a mean domain score of 3 or more.
Depressive Symptoms
The EPDS is a 10-item self-report, depressive symptoms screening questionnaire that has been validated for the identification of depressive symptoms over the previous 7 days in pregnant and postpartum women. Scores range from 0 to 30; higher scores indicate more depressive symptoms. A threshold of 9/10 has been suggested as an appropriate threshold for routine use in primary care to identify women with depressed mood. Thus, in the present study women with a score ≥10 were classified as having depressive symptoms. However, it has also been suggested that a higher threshold (e.g. EPDS ≥ 15) may be more appropriate for pregnant women due to the heightened anxiety during gestation; analyses were therefore repeated for this subgroup.
Other Cariables
Other variables extracted from medical records included demographics (age, race, educational level, marital status), height, weight, and parity. Obesity was defined as a pre-pregnancy Body Mass Index (BMI) ≥30 kg/m. Data were also collected on previous history of depressive disorder, current diagnosis of depressive disorder, previous or family history of gestational hypertension or pre-eclampsia, smoking status, a diagnosis of chronic hypertension, gestational hypertension, pre-eclampsia, or gestational diabetes. The latter diagnoses were obtained from medical coding using the International Classification of Diseases, 9th edition (ICD-9) and were verified using medical records.
Statistics
All data obtained were double-entered into a database and analyzed with SPSS (version 19.0, IBM). Histograms, box-plots, and descriptive methods were used to examine data for errors and outliers. Between-group comparisons of continuous variables (EPDS score, maternal age, BMI, and gestational age) were conducted with t-tests (snoring vs. no snoring). Dichotomized variables (positive screen for depressive symptoms vs. negative screen for depressive symptoms) were compared with Chi Square tests. Correlations between continuous variables (EPDS score, sleep duration, sleep quality score, and daytime function score) were conducted using Pearson's Correlation Coefficient. Logistic regression was used to determine associations between snoring and depressive symptoms after adjusting for potential covariates where appropriate (including maternal race, pre-pregnancy obesity, parity, educational level, presence of a partner, pre-eclampsia, diabetes, sleep quality score). Odds ratios (OR) and 95% Confidence Intervals (CI) were calculated. A p-value <0.05 was considered statistically significant.