Hotlines

The self-administered FFQ "What do you eat" was developed at the Robert Koch Institute to assess the usual intake of several food groups in the KiGGS core survey (2003-2006). The food groups most often consumed by children and adolescents were selected based on data from previous surveys and the advice of nutrition survey experts [17 (link)]. Questions on the frequency and the amount of 45 food items consumed "during the last few weeks" were included. Additional questions related to specific nutritional demands (multivitamin tablets, convenience foods, light products). The frequency of consumption was assessed using ten response categories: never, once a month, two to three times a month, once or twice a week, three to four times a week, five to six times a week, once a day, two to three times a day, four to five times a day, more than five times a day. In addition, participants were asked to indicate the portion size of the food items, which was given in five item-specific categories. Several pictures were used to illustrate portion sizes. The time frame "during the last few weeks" for the FFQ was based on pre-test experience, since some participants reported that it was difficult to give an answer for exactly "the last four weeks". However, the predefined answer categories for the frequency of consumption imply a time frame of about four weeks, since the lowest frequencies relate to a frequency per month (once a month, two to three times a month). The FFQ and a covering letter were sent to the respondents by postal mail three to four weeks prior to the visit. The first page of the FFQ provides instructions on completing the questionnaire. During the survey period a telephone hotline offered support with completing the questionnaire. Furthermore, support was offered when questionnaires were collected on local visit for the DISHES interview. The development process and design are described in detail elsewhere [17 (link)].
The DISHES interview is a modified diet history interview for assessing the usual dietary intake, with a reference period of the last four weeks. This was used as reference instrument. The DISHES software facilitates a standardized, structured and interviewer-guided assessment. The procedure has a meal-based structure similar to many 24-hour recall instruments. It is standardized, but still open-ended and allows the assessment of all possible food items in detail. The DISHES interview was conducted by trained nutritionists at the residence of the participants. First, usual meal patterns were obtained. In the next step, food intakes consumed during each meal were assessed by a check list. Subsequently, the frequency and portion size of each food consumed at the different meals was determined in detail. Additional food items could be chosen by searching the food code database. In general, estimation of portion sizes was facilitated using standardized tableware models. In addition, a picture book adapted from the EPIC-SOFT Picture Book [18 ] could be used to determine the portion size of selected food items. The DISHES software codes food items and connects the codes with the German Food Code and Nutrient Database (BLS II.3), which includes 10,654 food codes [19 (link)]. For the EsKiMo study, the software was adapted for the target group of adolescents (DISHES Junior). Additional foods (1,225 food codes), not yet available in the BLS but often consumed by adolescents, were incorporated into the database. The average duration of an interview in the EsKiMo Study was 49 minutes. The instrument had been previously validated for adults [13 (link)] and used in several national nutrition surveys [16 (link),20 (link),21 (link)].
In the KiGGS study (2003-2006), the parents were asked about their income, occupational status and education. This information was used to calculate a family socio-economic status index, developed for the survey. The index was categorized into low (3-8 points), medium (9-14 points) and high (15-21 points) [22 ]. According to this index, 27.5% of the KiGGS participants were allocated to the low, 45.4% to the medium, and 27.1% to the high socio-economic status group [23 (link)]. Furthermore, the body weight and height of the adolescents was assessed by standardized measurement. The body mass index (BMI) was calculated from body height and weight. According to the Kromeyer-Hauschild method, participants with a BMI above the 90^th percentile of the age- and gender-specific reference values were categorized as overweight [24 ].

Dependent variable: patient participation in COVID-19 triage recommendation is defined as the patient’s subsequent action adherence to the telephone triage recommendation within 14 days of the initial triage call in the three-month phase. Independent variables include demographic characteristics (age, gender), comorbidity (Charlson comorbidity index and obesity status), health behaviors (smoking, drinking, and illicit drug use), and symptoms (fever, unexplained muscle aches, eye-nose-throat (ENT) symptoms, eye symptom-(i.e., eye redness and/or discharge, respiratory symptom, upper respiratory infection (URI) symptom, gastrointestinal (GI symptom), and altered mental status).
Charlson comorbidity index (CCI) is a weighted index as a continuous variable to predict the risk of death within one year of hospitalization for patients with specific comorbid conditions. Higher scores indicate a more severe condition and a poorer prognosis and have been used consistently in the literature [13 (link)]. Body Mass Index (BMI) was defined as the body mass (kg) divided by the square of the height (m²) and was calculated using self-reported weight and height. We defined obesity as having a BMI equal to or above 30 [14 (link)]. This was a dichotomous variable. Health behaviors included smoking, drinking, and illicit drug use as binary variables (0 = never, 1 = quit or currently use). COVID-related symptoms included fever, unexplained muscle aches, ENT, eye symptoms, respiratory symptoms, URI symptoms, GI symptoms, and altered mental status, which were included in the hotline nursing triage (0 = No, 1 = Yes).

Data for this study were obtained from longitudinal online surveys that were conducted annually from 2018 to 2020. The surveys asked questions on general well-being and suicidality, and this initiative was led by the Centre for Suicide Research and Prevention (CSRP) at the University of Hong Kong (HKU). Targeted study samples were 10–35 year-old individuals living in the general Hong Kong population, particularly those with known risk factors of suicide such as previous suicidal ideation and attempt, and psychiatric disorders.
For the first survey wave, links to the online survey were disseminated through poster promotions, emails to members, newsletters, and Facebook and web pages of the authors’ affiliated institutions. Additionally, for maximum outreach to the targeted participants, links to the survey were also disseminated as (i) poster promotions at branches, and (ii) notices to members of, three community outreach organizations: Caritas, Hong Kong Federation of Youth Groups, and The Boys’ and Girls’ Clubs Association of Hong Kong. All three are major outreach organizations with territory-wide service centers that provide counseling and social work services to individuals up to 35 years of age^{26 –28} .
Clicking the survey link would direct participants to a secure webpage containing the survey. Participants could choose to fill out either a Chinese or English version. Written informed consent was first obtained from all participants, and they were informed of the survey’s purpose (gaining an in-depth understanding of their demographic group’s general well-being), approximate survey duration (ten minutes), strict confidentiality of their data, and of their freedom to discontinue at any time. Careful consideration was taken to ensure that the survey questions would incur no risk and pose the least stress to participants. Contact information for emotional support hotlines and services was made available throughout the survey to encourage distressed participants to seek support immediately. Participants who consented to be contacted further for follow-up could provide their email addresses, where survey links were sent in the subsequent survey collection period.
All procedures & protocols adopted in this study were approved by the Human Research Ethics Committee for Non-Clinical Faculties of HKU under the reference number EA1709039. Consent from parents or legal guardians for under-aged participants was deemed not required by the committee as the endorsed study was assessed to pose minimal potential harm to under-aged participants. Survey collection periods for 2018, 2019, and 2020 waves were 22 December 2017–15 July 2018, 5 June–8 July 2019, and 29 June–29 September 2020 respectively. In 2019 and 2020 survey waves were follow-up surveys from the previous wave, and thus did not involve any recruitment of new participants.