On the feasibility of measuring physiologic and self-reported sleep disturbance by aircraft noise on a national scale: A pilot study around Atlanta airport.

Aircraft noise can disturb sleep and impair recuperation. Research is needed to develop exposure-response relationships that are representative of noise-exposed communities and can be used to inform noise mitigation policy in the United States. For a national field study on physiologic response to aircraft noise during sleep to be feasible, an inexpensive yet sound study methodology is needed. In the pilot study presented here, the methodology of using electrocardiography and actigraphy to monitor sleep was implemented around Atlanta Hartsfield-Jackson International Airport (ATL). The primary objective was to evaluate the quality and quantity of data that could be obtained with the following study approaches: recruiting participants by postal questionnaire, shipping them the physiologic and noise measurement equipment, and the unattended setup of the equipment and recording of data by the participants themselves. The secondary objective was to compare objective and subjective measures of sleep and health between groups exposed to different levels of nocturnal aircraft noise. We mailed 4080 questionnaires containing items on sleep, health and noise disturbance to residences around ATL that were exposed to at least 35 dB Lnight aircraft noise. From 407 questionnaire respondents, 34 participants completed five nights of unattended sleep measurements. Data of sufficient quality and quantity to investigate the effects of aircraft noise on sleep were obtained. Self-reported awakenings increased as a function of the highest maximum aircraft noise level occurring during the sleep period. Event-related physiologic awakenings increased as a function of the maximum noise level of individual aircraft noise events, although this effect was of only borderline statistical significance (p = 0.057) likely due to the low sample size of this pilot study. The approach used in the presented pilot study has been demonstrated to be feasible for the purpose of the larger-scale study among a representative population around multiple airports in the future.

Effectiveness of incentives and follow-up on increasing survey response rates and participation in field studies.

BACKGROUND: Questionnaires are valuable data collection instruments in public health research, and can serve to pre-screen respondents for suitability in future studies. Survey non-response leads to reduced effective sample sizes and can decrease representativeness of the study population, so high response rates are needed to minimize the risk of bias. Here we present results on the success of different postal questionnaire strategies at effecting response, and the effectiveness of these strategies at recruiting participants for a field study on the effects of aircraft noise on sleep. METHODS: In total, we mailed 17 rounds of 240 questionnaires (total n = 4080) to randomly selected households around Atlanta International Airport. Different mailing rounds were varied in the length of the questionnaire (11, 26 or 55 questions), survey incentive (gift card or $2 cash), number of follow-up waves (0, 2 or 3), incentive for participating in a 5-night in-home sleep study ($100, $150 or $200), and address personalization. RESULTS: We received completed questionnaires from 407 respondents (response rate 11.4%). Personalizing the address, enclosing a $2 cash incentive with the initial questionnaire mailing and repeated follow-up mailings were effective at increasing response rate. Despite the increased expense of these approaches in terms of each household mailed, the higher response rates meant that they were more cost-effective overall for obtaining an equivalent number of responses. Interest in participating in the field study decreased with age, but was unaffected by the mailing strategies or cash incentives for field study participation. The likelihood that a respondent would participate in the field study was unaffected by survey incentive, survey length, number of follow-up waves, field study incentive, age or sex. CONCLUSIONS: Pre-issued cash incentives and sending follow-up waves could maximize the representativeness and numbers of people from which to recruit, and may be an effective strategy for improving recruitment into field studies.

Survey Results of a Pilot Sleep Study Near Atlanta International Airport.

Aircraft noise can disturb the sleep of residents living near airports. To investigate potential effects of aircraft noise on sleep, recruitment surveys for a pilot field study were mailed to households around Atlanta International Airport. Survey items included questions about sleep quality, sleep disturbance by noise, noise annoyance, coping behaviors, and health. Of 3159 deliverable surveys, 319 were returned (10.1%). Calculated outdoor nighttime aircraft noise (Lnight) was significantly associated with lower sleep quality (poor or fair; odds ratio (OR) = 1.04/decibel (dB); p < 0.05), trouble falling asleep within 30 min ≥1/week (OR = 1.06/dB; p < 0.01), and trouble sleeping due to awakenings ≥1/week (OR = 1.04/dB; p < 0.05). Lnight was also associated with increased prevalence of being highly sleep disturbed (OR = 1.15/dB; p < 0.0001) and highly annoyed (OR = 1.17/dB; p < 0.0001) by aircraft noise. Furthermore Lnight was associated with several coping behaviors. Residents were more likely to report often or always closing their windows (OR = 1.05/dB; p < 0.01), consuming alcohol (OR = 1.10/dB; p < 0.05), using television (OR = 1.05/dB; p < 0.05) and using music (OR = 1.07/dB; p < 0.05) as sleep aids. There was no significant relationship between Lnight and self-reported general health or likelihood of self-reported diagnosis of sleep disorders, heart disease, hypertension or diabetes. Evidence of self-reported adverse effects of aircraft noise on sleep found in this pilot study warrant further investigation in larger, more representative subject cohorts.

Aircraft Noise Effects on Sleep-Results of a Pilot Study Near Philadelphia International Airport.

Current objective data on aircraft noise effects on sleep are needed in the US to inform policy. In this pilot field study, heart rate and body movements were continuously measured during sleep of residents living in the vicinity of Philadelphia International Airport (PHL) and in a control region without aircraft noise with sociodemographic characteristics similar to the exposed region (N = 40 subjects each). The primary objective was to establish the feasibility of unattended field measurements. A secondary objective was to compare objective and subjective measures of sleep and health between control and aircraft noise exposed groups. For all measurements, there was less than 10% of data loss, demonstrating the feasibility of unattended home measurements. Based on 2375 recorded aircraft noise events, we found a significant (unadjusted p = 0.0136) exposure-response function between the maximum sound pressure level of aircraft noise events and awakening probability inferred from heart rate increases and body movements, which was similar to previous studies. Those living near the airport reported poorer sleep quality and poorer health than the control group in general, but when asked in the morning about their last night's sleep, no significant difference was found between groups. Neither systolic nor diastolic morning blood pressures differed between study regions. While this study demonstrates the feasibility of unattended field study measurements, for a national study around multiple US airports refinements of the study design are necessary to further lower methodological expense and increase participation rates.

The effects of resistance exercise on cocaine self-administration, muscle hypertrophy, and BDNF expression in the nucleus accumbens.

BACKGROUND: Exercise is associated with positive outcomes in drug abusing populations and reduces drug self-administration in laboratory animals. To date, most research has focused on aerobic exercise, and other types of exercise have not been examined. This study examined the effects of resistance exercise (strength training) on cocaine self-administration and BDNF expression, a marker of neuronal activation regulated by aerobic exercise. METHODS: Female rats were assigned to either exercising or sedentary conditions. Exercising rats climbed a ladder wearing a weighted vest and trained six days/week. Training consisted of a three-set "pyramid" in which the number of repetitions and resistance varied across three sets: eight climbs carrying 70% body weight (BW), six climbs carrying 85% BW, and four climbs carrying 100% BW. Rats were implanted with intravenous catheters and cocaine self-administration was examined. Behavioral economic measures of demand intensity and demand elasticity were derived from the behavioral data. BDNF mRNA expression was measured via qRT-PCR in the nucleus accumbens following behavioral testing. RESULTS: Exercising rats self-administered significantly less cocaine than sedentary rats. A behavioral economic analysis revealed that exercise increased demand elasticity for cocaine, reducing consumption at higher unit prices. Exercising rats had lower BDNF expression in the nucleus accumbens core than sedentary rats. CONCLUSIONS: These data indicate that resistance exercise decreases cocaine self-administration and reduces BDNF expression in the nucleus accumbens after a history of cocaine exposure. Collectively, these findings suggest that strength training reduces the positive reinforcing effects of cocaine and may decrease cocaine use in human populations.

Exercise decreases speedball self-administration.

AIMS: Epidemiological studies report that individuals who exercise are less likely to abuse drugs. Preclinical studies report that exercise, in the form of treadmill or wheel running, reliably decreases the self-administration of psychomotor stimulants and opioids. To date, preclinical studies have only examined the effects of exercise on responding maintained by individual drugs and not by combinations of multiple drugs. This limits the translational appeal of these studies because polydrug abuse is common among substance abusing populations. The purpose of this study was to examine the effects of exercise on the self-administration of speedball, a combination of cocaine and heroin that is frequently encountered in intravenous drug abusing populations. MAIN METHODS: Female rats were obtained at weaning and assigned to sedentary or exercising conditions. Sedentary rats were housed in standard cages that permitted no exercise beyond normal cage ambulation; exercising rats were housed in similar cages with an activity wheel. After 6weeks, rats were implanted with intravenous catheters and trained to self-administer cocaine, heroin, and dose combinations of cocaine and heroin (i.e., speedball) on a progressive ratio schedule of reinforcement. KEY FINDINGS: Doses of speedball maintained greater levels of responding than corresponding doses of cocaine and heroin alone. Importantly, responding maintained by cocaine, heroin, and speedball was lower in exercising rats than sedentary rats. SIGNIFICANCE: These data indicate that exercise decreases the self-administration of speedball and suggest that exercise may reduce the abuse of drug combinations that have traditionally been resistant to treatment.

The effects of exercise on cocaine self-administration, food-maintained responding, and locomotor activity in female rats: importance of the temporal relationship between physical activity and initial drug exposure.

Previous studies have reported that exercise decreases cocaine self-administration in rats with long-term access (8+ weeks) to activity wheels in the home cage. The purpose of this study was to (a) examine the importance of the temporal relationship between physical activity and initial drug exposure, (b) determine the effects of exercise on responding maintained by a nondrug reinforcer (i.e., food), and (c) investigate the effects of exercise on cocaine-induced increases in locomotor activity. To this end, female rats were obtained at weaning and divided into 4 groups: (a) EXE-SED rats were housed in exercise cages for 6 weeks and then transferred to sedentary cages after the first day of behavioral testing; (b) SED-EXE rats were housed in sedentary cages for 6 weeks and then transferred to exercise cages after the first day of behavioral testing; (c) SED-SED rats remained in sedentary cages for the duration of the study; and (d) EXE-EXE rats remained in exercise cages for the duration of the study. Relative to the sedentary group (SED-SED), exercise reduced cocaine self-administration in both groups with access to activity wheels after initial drug exposure (EXE-EXE, SED-EXE) but did not reduce cocaine self-administration in the group with access to activity wheels only before drug exposure (EXE-SED). Exercise also decreased the effects of cocaine on locomotor activity but did not reduce responding maintained by food. These data suggest that exercise may reduce cocaine use in drug-experienced individuals with no prior history of aerobic activity without decreasing other types of positively reinforced behaviors.