Stimulus control and affect in dietary behaviours. An intensive longitudinal study.

BACKGROUND: Dietary behaviours are substantially influenced by environmental and internal stimuli, such as mood, social situation, and food availability. However, little is known about the role of stimulus control for eating in non-clinical populations, and no studies so far have looked at eating and drinking behaviour simultaneously. METHOD: 53 individuals from the general population took part in an intensive longitudinal study with repeated, real-time assessments of eating and drinking using Ecological Momentary Assessment. Eating was assessed as main meals and snacks, drinks assessments were separated along alcoholic and non-alcoholic drinks. Situational and internal stimuli were assessed during both eating and drinking events, and during randomly selected non-eating occasions. Hierarchical multinomial logistic random effects models were used to analyse data, comparing dietary events to non-eating occasions. RESULTS: Several situational and affective antecedents of dietary behaviours could be identified. Meals were significantly associated with having food available and observing others eat. Snacking was associated with negative affect, having food available, and observing others eat. Engaging in activities and being with others decreased the likelihood of eating behaviours. Non-alcoholic drinks were associated with observing others eat, and less activities and company. Alcoholic drinks were associated with less negative affect and arousal, and with observing others eat. CONCLUSIONS: RESULTS support the role of stimulus control in dietary behaviours, with support for both internal and external, in particular availability and social stimuli. The findings for negative affect support the idea of comfort eating, and results point to the formation of eating habits via cue-behaviour associations.

Compliance with an EMA monitoring protocol and its relationship with participant and smoking characteristics.

INTRODUCTION: Arguably, the greatest advantage of ecological momentary assessment (EMA) studies is that data are collected repeatedly in real-time and real-world situations, which reduces recall and situational biases and thus improves the accuracy and validity of the data collected. However, the validity of EMA data is contingent upon compliance rates. If participant characteristics are related to missing data, analyses should control for these factors, or they should be targeted in EMA training sessions. This study evaluates the impact of demographic and smoking-related participant characteristics on compliance to an EMA smoking study protocol. METHODS: Prequit-day data were taken from the control arm of an ongoing randomized controlled trial of a smoking-cessation program. After training, 119 participants were asked to carry a mobile device with them at all times for ~6 days and to log every cigarette they smoked in addition to completing randomly scheduled assessments. Different types of compliance were assessed: the percentage of completed random prompts (signal-contingent compliance), the percentage of logged cigarettes per day compared to a timeline follow-back measure, and the correlation between logged cigarettes and a carbon monoxide assessment 2 hr later (both event-contingent compliance). RESULTS: Overall compliance rates were 78.48% for event-contingent and 72.17% for signal-contingent compliance. None of the demographic or smoking-related participant characteristics predicted signal-contingent compliance; however, female participants showed higher event-contingent compliance than male participants, and Caucasian participants showed higher event-contingent compliance than non-Caucasian participants. CONCLUSIONS: Compliance did not depend on smoking-related characteristics. EMA is a valid method for assessing smoking behavior in real-time and real-world settings.