Public call one – primary research studies eligibility criteria and research questions

Eligibility criteria

Primary research studies will be screened against eligibility criteria before being considered for inclusion in the revision. Eligible citations will be checked to ensure that the studies have not been retracted. Retracted studies will be excluded.

Eligibility criteria for existing primary studies

To be considered suitable for use, primary research studies must:

• be a peer-reviewed primary study in humans
• address one or more of the research questions and its associated populations, exposures, comparators and outcomes (see Research questions below)
• have been published from 2009 onwards for any study examining ultra-processed foods
• have been published from 1995 onwards for any study examining any topic other than ultra-processed foods
• be published in English.

The following will be excluded:

• studies of nutritional supplements or nutrient-specific interventions (including protein supplements). Nutritional (or dietary) supplements are products added to the diet, usually in the form of a pill, capsule, tablet, powder or liquid. They contain one or more dietary ingredients such as vitamins, minerals, herbs, amino acids and enzymes.
• systematic reviews
• non-peer-reviewed literature.

Eligible primary studies will be considered for inclusion in the recently commissioned evidence reviews.

Research questions

To be considered for use in the review, a primary study must relate to one of the research questions. These research questions were chosen by the Dietary Guidelines Expert Committee based on the prior scoping and mapping work. The research questions are:

• dietary patterns versus a different dietary pattern/low adherence to the same dietary pattern and incidence of anxiety or depression in adults, children and adolescents or incidence of pre/post-natal depression during pregnancy and breastfeeding (question 1)
• high versus low consumption of ultra-processed food (UPF) in children and adolescents (2–17 years of age) on the outcomes of: incident anxiety and depression; development of asthma; development of dietary allergies and development of developmental neurocognitive conditions (question 2)
• the impact of dietary patterns, source of protein or UPF consumption during pregnancy and breastfeeding on maternal and birth outcomes (question 3)
• high versus low consumption of UPF in adults on the outcomes of: all-cause mortality; cardiovascular events and cardiovascular mortality; incidence of type 2 diabetes; cancer events and cancer mortality; and incidence of anxiety and depression (question 4).

Each research question comprises a population of interest, an intervention or exposure of interest, a comparator of interest, and one or more outcomes of interest. Collectively, these parameters are known as the ‘PI/ECO’ criteria.

Further detail on the PI/ECO criteria for the above research questions are listed in the Tables below.

To be eligible for consideration, primary studies must address the PI/ECO criteria listed in the tables, including:

• the associated Population (the general Australian population) AND
• one of the priority Exposure and Comparison pairs (for example, high versus low intake of plant foods) AND
• at least one of the in-scope Outcomes (for example, newly diagnosed cardiovascular disease).

* Defined as the quantities, proportions, variety, or combination of foods and drinks typically consumed

Animal protein-rich foods include meat and poultry, seafood, eggs and dairy (milk, yoghurt and cheese). Plant protein-rich foods include legumes, nuts and seeds, tofu and plant-based meat alternatives.