Assessing longitudinal associations between diet, social connectedness, and psychological distress among adolescents living in Western Sydney, Australia

Abstract

This thesis examined the impact of diet (fruit, vegetable, and fast food consumption) and social connectedness levels (low versus high) on psychological distress among younger (12-15-year-olds) and older (16-19-year-olds) adolescents in Western Sydney, Australia. Adolescent Health Study is a unique study that prospectively followed adolescents for a 13- week period and collected real-time data using the Ecological Momentary Assessment (EMA). Adolescents were recruited from the general population through social media platforms like Instagram and Facebook. All study participants (n = 1277) downloaded a free- of-cost mobile phone application, Ethica, to EMA questions. All results in this thesis are reported and stratified by age (younger and older adolescents) and gender (male and female). The study sample consisted of 228 males and 1049 females. Study 1 comprised on 389 participants, yielding 834 observations, whereas study 2 comprised of 1255 participants, resulting in 1976 observations. All analyses for this thesis adjusted for age, gender, and physical activity levels. Study 1 examined the role of diet as a mediator between social connectedness and psychological distress and determined if psychological distress scores were different among those with low versus high social connectedness. It reported that the total effect of social connectedness on psychological distress was significant (β = - 1.80, 95% CI [-2.76, -0.82], p < .001), and the relationship was negative. That is, the greater the social connectedness, the lower the level of psychological distress. The indirect effect was 0.07 * 0.12 = 0.084 and was statistically non-significant. It also determined that social connectedness and diet at time 1 predicted psychological distress at time 2, thereby establishing the causal association between the two. Study 2 determine if psychological distress levels were less marked among the adolescents with high social connectedness, after the implementation of COVID-19 restrictions. It used the linear mixed regression model to predict the level of psychological distress pre- and post-COVID-19 restrictions among adolescent participants. It reported that the COVID-19 restrictions positively predicted higher scores on the K6 (β = 0.63, 95% CI[- 0.09, 1.35]). However, this finding was not significant. There were three variables significantly associated with higher psychological distress scores on Kessler-6 (K6) : gender, social connectedness, and fast food consumption. Being male was associated with a lower K6 score (β = -2.21, 95% CI[-3.54, -0.89]). Similarly, the high social connectedness group was also associated with a lower K6 score (β = -1.01, 95% CI[-1.38, -0.64]). The number of fast food units consumed was positively associated with K6 (β = 0.29, 95% CI[0.05, 0.54]). Thus, both studies in this thesis consistently reported across all the analyses that being female, scoring low on social connectedness, and having higher fast-food consumption were associated with high psychological distress scores. The latter can be explained by unequal sample distribution of the sample before and after COVID-19 restrictions (662 versus 64 observations). Future studies should consider adjusting for socioeconomic status for the mediation analysis and include other varieties of food such as cereals, legumes, or meat consumption.

Date of Award	2023
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Elizabeth Conroy (Supervisor)