research thesis proposal written and oral.

Estimating energy deficiency is essential to assess the risk of developing the female

athlete triad, which consists of menstrual dysfunction and impaired bone health caused by low

energy availability (EA) (De Souza et al., 2014). A fast, feasible, and reliable tool for clinical use

is yet to be designed. The aim of this study is to develop and validate the Female Energy

Deficiency Questionnaire (FED-Q), a tool to assess energy deficiency (ED) in exercising women.

We hypothesize that ED can be predicted with 90% sensitivity by the Female Energy Deficiency

Questionnaire – FED-Q, a survey that screens for: the presence of menstrual dysfunction;

impaired bone health; exercise level; dietary habits; and eating disorders and disordered eating.

Secondary hypotheses are: 1. the total score in the FED-Q will correlate with resting metabolic

rate ratio (RMRratio) and total triiodothyronine concentration; 2. the specific scores for menstrual

dysfunction and bone health will be associated and correlated, respectively, with menstrual status

and bone mineral density. Our null hypothesis is: a questionnaire that screens for the presence

of menstrual dysfunction, impaired bone health, exercise level, dietary habits, and eating

disorders and disordered eating is not an accurate predictor of energy deficiency in exercising

women.

Low EA and ED can be caused by high exercise energy expenditure that is not sufficiently

compensated with energy intake. EA is calculated as the difference between exercise energy

expenditure and dietary energy intake per kilograms of fat-free mass per day ([EEE-DEI]/kg

FFM/day). Low EA is defined as EA < 30 kcal/kg FFM/day. Persons with low EA are likely to be

energy deficient, a common condition among female athletes and non-athlete exercising women.

There is no gold-standard for the assessment of ED, but serum triiodothyronine (TT3 <80 ng/dL)

and resting metabolic rate ratio (RMRratio = RMRmeasured/RMRpredicted <0.9) have been used as

parameters of ED (Strock et al., 2020a; Strock et al., 2020b; De Souza et al., 2014).

When an individual is energy deficient, their organism does not have enough fuel for all

basic physiological needs, and the systems that are most important to survival are prioritized.

Reproduction is one of the first functions to be impaired because of low EA/ED (De Souza et al.,

2014). Previous studies have reported high prevalence of menstrual dysfunction in exercising

women, which was higher than that observed in sedentary women (De Souza et al., 2010; De

Souza et al., 1998). One study comparing active and sedentary females found that more than

50% of the participants in the exercising group were anovulatory, condition not observed in any

of the subjects in the sedentary group (De Souza et al., 2010). In addition, anovulatory exercising

women have been reported to have lower energy intake compared to both active and sedentary

eumenorrheic women, evidencing the relationship between inadequate fueling and menstrual

dysfunction (De Souza et al., 1998).

Growth is also impaired in women with low EA, which, in more severe cases, may impact

bone mineral density (BMD). Compared to women with normal BMD, females with low BMD were

reported to exercise more and to have lower body fat percentage and fat mass. Age of menarche

was found to be higher, which could be indicative of delayed menarche and menstrual dysfunction

(Gibbs et al., 2014). Menstrual dysfunction and impaired bone health as consequences of low EA

are the components of the Female Athlete Triad (Triad), which can include more severe cases

with low BMD and eating disorders or disordered eating (De Souza et al., 2014).

As low EA and ED are the main cause for the impaired health outcomes, early and precise

detection of low EA/ED risk is needed. Measurements of EEE and DEI – used to calculate EA –

depend on self-reported data and depend on predictive equations, hence assessing EA is less

accurate than measuring ED. In a study comparing exercising women with and without functional

hypothalamic amenorrhea, the first group was found to have lower ED, but similar EA, indicating

that the measures used to assess ED are more sensitive to altered metabolic function than EA

(Strock et al., 2020c). However, for clinical assessments, examining TT3 and RMRratio may not be

feasible methods, in terms of cost, time, and access. Blood serum analyses and the use of a

metabolic analyzer are not rapid measures and may not be easily accessed by all physicians,

dietitians, nutritionists, or athletic trainers.

Aiming to provide sports and health care professionals with an appropriate tool, studies

presented different questionnaires that attempted to estimate low EA. While some of them were

developed specifically for this purpose, other surveys that were tested are intended for screening

different conditions that could be related to EA and the Triad. These are related to eating

disorders, dietary habits, and body image. Of all available questionnaires, only a few have gone

through a complete validation process and only one has been validated for use with adult female

athletes (Sim & Burns, 2021).

To our knowledge, the Low Energy Availability in Females Questionnaire (LEAF-Q),

proposed by Melin et al. (2014) is currently the only validated survey to estimate low energy

availability in female athletes. Even though it seems to be a promising tool, the LEAF-Q has

several limitations. A cut-off value (score ≥ 8) was used to determine if a participant was at risk of

developing the Triad. The LEAF-Q was considered to have accurate sensitivity if it had detected

any of the three Triad-related outcomes – low EA, menstrual dysfunction, and impaired bone

health –, therefore neither ED nor low EA were considered strictly necessary to correctly identify

a positive case. This raises concerns, because positive cases of low BMD or menstrual

dysfunction do not necessarily mean that those were caused by low EA. More importantly, there

were no significant differences in EA between groups above and below the cut-off point, meaning

that the LEAF-Q can lead to concerning misinterpretations. In addition, the study of Rogers et al.

(Rogers et al., 2021) showed that the LEAF-Q has a high sensitivity, but a very low specificity in

the assessment of risk of Triad outcomes, therefore very low positive predictive values. The

authors also found the score not to be related to RMRratio, indicating that it is likely inappropriate

for assessing EA or ED.

Given the evidence in literature, it has been observed that there are no clinically reliable

and valid tools to assess ED in exercising women. A questionnaire with the purpose of assessing

low EA and/or ED must assess menstrual status, dietary habits, exercise level, and bone health.

For better accuracy, validation should be assessed with correlations not only with EA, but mainly

with RMRratio and serum TT3.