Low energy availability and risk factors in non-athletic females in New Zealand : a thesis presented to Massey University in partial fulfilment of requirements for the degree of : Master of Science (MSc) in Nutrition and Dietetics

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Background: Low energy availability (LEA) has primarily been studied in athletic females with few studies examining the risk factors among healthy non-athletic females aged 18-30 years. Low energy availability can occur intentionally or unintentionally and may result from dietary manipulations or changes to exercise behaviours which can lead to long term negative health implications. Low energy availability has been shown to have a negative impact on bone health, menstrual function, psychological well-being, immune function, gastrointestinal function and metabolism. Therefore, understanding some of the risk factors of LEA in non-athletic females, inclusive of perceptions of eating and exercise, may allow for early identification of habits that contribute to LEA. Method: The risk of LEA was determined using a validated screening tool; low energy availability in females questionnaire (LEAF-Q) which was completed through an online survey. Additional risk factors of LEA were further identified using the New Zealand Physical Activity Questionnaire - short form, Clinical Impairment Assessment (CIA) Questionnaire and Eating Disorder Questionnaire. Physical activity was further categorised across the week into low (<5 days of moderate and/or vigorous activity), moderate (≥5 and <10 days moderate and/or vigorous activity) and high (≥10 days moderate and/or vigorous activity) physical activity groups. Participants: A total of 531 participants took part in the online questionnaire, of which 151 participants met the inclusion criteria for this study and were subsequently included in the analysis. Participants were predominantly New Zealand European (78.4%) with an average body mass index 23.8 ± 4.6 kg·m-2 and age 23 ± 3.2 years. Results: Over half of the participants (51.0%) were classified as at risk of LEA based on the LEAF-Q scoring. The majority of participants (52.3%) used oral contraceptive pills. Of the females not using the oral contraceptive pill, 64.2% reported having normal menstruation and 29.1% reported they did not have normal menstruation. Although not significant, those who had irregular menstruation had higher sores across all three CIA components. Clinical impairment assessment global score on average was 10.3 ± 10.4, with 22.5% of all participants having a high level of impairment (≥48). Individuals with a high level of impairment had significantly higher LEAF-Q scores across all three CIA components; eating habits (p<0.001), exercise habits (p=0.002) and body shape (p=0.002). The study demonstrated 26.5% of participants were classified as having low physical activity levels, 42.4% as moderate physical activity levels and 31.1% as reaching high levels of physical activity. One-way ANOVA between physical activity groups (low/moderate/high) and LEAF-Q score demonstrated a significant positive difference (p=0.025). There was a significant positive relationship between the number of days of vigorous physical activity and LEAF-Q score (p=0.038). Conclusion: This cross-sectional study adds to the current literature that investigates eating and exercise behaviours and the subsequent influence of LEA in healthy but non-athletic females in New Zealand. This study highlights the multi-directional relationships between exercise and eating behaviours and LEA risk. Non-athletic females in this current study presented with poor perceptions towards eating and body weight based on the CIA questionnaire which may place them at risk of LEA. Subsequently, non-athletic females may present with symptoms associated with chronic LEA. Early detection of LEA is needed among exercising females, given the consequences of LEA in the short and long term, early detection can enable early intervention and reduce the risk to long term health.