Background
Leading a healthy lifestyle by engaging in behaviours such as healthy eating, and regular exercise are well-established contributors to good health and successful aging [
1]. Nonetheless, developed nations such as Singapore have seen a marked rise in largely preventable chronic medical conditions such as hypertension, diabetes, high total cholesterol, and obesity [
2]. Given the multitude of health benefits that adopting a healthy lifestyle confers, it is unsurprising that there has been greater focus directed towards promoting healthier lifestyle choices amongst citizens to curb the issue. In recent years, such efforts have shifted toward a more nuanced approach through the application of behavioural insights to influence decision making; a concept known as nudging [
3,
4].
Nudging can be broadly defined as “any aspect of the choice architecture that alters people’s behaviour in a predictable way without forbidding any options, or significantly changing their economic incentives” [
5]. Generally, nudges act as a low-cost, less intrusive method of public policy. While nudges have been widely used in the public domain, one area of interest is the usage of nudges as a mean of promoting healthier lifestyle choices [
6,
7]. Examples of a health-nudge would relate to the replacement of unhealthy products (such as sweets) with healthier ones (protein bars) at supermarket checkouts so that people would select the healthier product instead. The influence on decision-making of such an approach is that it may potentially have a significant effect on public health without forcing anyone to commit to or do anything at all. A meta-analysis of 37 papers on the efficacy of nudge theory found that on average, nudges were successful in increasing nutritional choices by up to approximately 15.3% [
8]. Given its effectiveness, there is an increasing global interest in testing and implementing nudges as a means of promoting healthy lifestyle [
9,
10].
While nudges are generally effective, there exists a rich debate surrounding the use of nudges, with proponents maintaining that nudges do not reduce autonomy, but increase it in some cases while critics claiming they are manipulative [
11]. Furthermore, some critics claim that nudges are used to achieve goals that are not particularly useful or helpful to the person or society [
12]. Accordingly, current literature provides further evidence highlighting the disparity in citizens’ views and endorsement of nudges across various nations. For example, Sunstein et al. [
13] reported markedly high approval ratings in Asian countries such as China and South Korea. Surveying 952 people in Sweden and the United States, Hagman et al. [
14] reported that strong majorities in both countries were in favour of a wide variety of nudges. Similarly, Krisam et al. [
15] reported a strong majority of German citizens endorsing nudges as an accepted method to promote health behaviours. Conversely, countries such as Hungary, Denmark and Japan reported relatively low scores of approvals [
13]. Specifically, while the majority in these nations do tend to approve of the tested nudges, the levels of approval are consistently low, and in some cases, approval rates fall below 50% [
16]. Owing to this disparity, it follows that determining the public’s perception towards nudges is an important precursor to the implementation of any form of nudge. Regardless of the type of intervention, public acceptance is considered to be one of three key aspects that should be taken into consideration prior to implementation [
17]. As reported in prior studies, public acceptance can play a defining role in the effectiveness of the nudge implemented to the extent that in some cases, such impact can be observed even when the majority of a population does not know of nudging [
15,
18]. Essentially, the evidences highlights that public acceptance can serve as a form of permission slip, whereby either widespread approval or disapproval can determine a predicted outcome which may serve to guide policy makers in their decision-making process [
16].
The aforementioned studies present valuable insights exploring public attitudes toward nudges across various nations. Yet, there remains relatively little work exploring the approval rates of nudges in the domain of healthy lifestyle within a multi-ethnic population like Singapore. Singapore is a multi-ethnic city-state situated in Southeast Asia with a population of approximately 5.6 million of which 4.1 million are Singapore residents (Singapore citizens or permanent residents) [
19]. The population largely comprises inhabitants from three major Asian ethnic groups: Chinese (76.0%), Malay (15.0%) and Indian (7.5%) [
20]. Given its diverse ethnic composition, a study in this setting provides a unique opportunity to elucidate acceptance towards healthy lifestyle nudges within a multi-ethnic population.
To address the gaps in current literature, the present study aims to: 1) investigate the levels of approval regarding healthy lifestyle nudges, and 2) identify socio-demographics and lifestyle behaviours (sedentary behaviour, physical activity, and dietary patterns) that are associated with acceptance of healthy lifestyle nudges.
Method
Participants and procedures
The data for this research comes from a population based, cross-sectional study aimed at evaluating the Knowledge, Practices and Attitudes towards Diabetes Mellitus (DM) amongst residents of Singapore aged 18 years and above. A more detailed methodology of the study can be found in an earlier paper [
21]. Briefly, the sample was randomly selected via a disproportionate stratified sampling design according to ethnicity (Chinese, Malay, Indian, Others) and age groups (18–34, 35–49, 50–64, 65 and above) from a national population registry database of all citizens and permanent residents within Singapore. The study oversampled certain minority populations, such as Malay and Indian ethnicities, as well as those above 65 years of age, in order to improve the reliability of the parameter estimates for these subgroups.
Citizens and permanent residents who were randomly selected were sent notification letters followed by home visits by trained interviewers from a survey research company to obtain their informed consent to participate in the study. Face-to-face interviews with those who were agreeable to participate were conducted in their preferred language (English, Mandarin, Malay, or Tamil). Responses were captured using computer assisted personal interviewing. Individuals who were unable to be contacted due to incomplete or incorrect addresses, or living outside of the country, or were incapable of attending the interview due to severe physical or mental conditions, language barriers, or were institutionalised or hospitalised at the time of the survey were excluded from the study. For those aged 18 to 20 years, parental consent was sought as the official age of majority in Singapore is 21 years and above. The study closed recruitment with a final response rate (total completed interview / [total number of sample – eligible cases]) of 66.2%.
Measures
Healthy lifestyle nudges questionnaire
The survey questionnaire built upon prior work limited to Europe [
16]. The version included a total of 15 items. To adjust to the Singapore context, this number was reduced to 8. The selection was categorised into three groups in terms of increasing intrusiveness: i) information government campaigns: purely government campaigns to educate individuals about healthy lifestyle choices ii) government mandated information: mandatory information nudges imposed by government requiring disclosure of nutritional value and health risk of food e.g. calorie labels in restaurants, high salt content warnings, nutritional traffic lights and iii) default rules and choice architecture for retailers to support healthy foods e.g. sweet-free cashier zones. Items were administered via a 5-point Likert scale ranging from 1 = “Strong Agree” to 5 = “Strongly Disagree”.
Chronic physical conditions
A modified version of the World Mental Health Composite International Diagnostic Interview (CIDI) version 3.0 checklist of chronic medical conditions was used, and the respondents were asked to report any of the conditions listed in the checklist [
22]. The question was read as, “I am going to read to you a list of health problems some people have. Has a doctor ever told you that you have any of the following chronic medical conditions?” This was followed by a list of 18 chronic physical conditions (such as asthma, high blood sugar, hypertension, arthritis, cancer, neurological condition, Parkinson’s disease, stroke, congestive heart failure, heart disease, back problems, stomach ulcer, chronic inflamed bowel, thyroid disease, kidney failure, migraine headaches, chronic lung disease, and hyperlipidaemia) which are prevalent among Singapore’s population.
Physical activity and sedentary behaviour
The Global Physical Activity Questionnaire (GPAQ) is a 16-item instrument developed by the World Health Organisation to measure physical activity [
23]. Translations of the GPAQ to Mandarin, Malay and English were permitted by the publisher. Respondents were asked about the duration and frequency of vigorous and moderate intensity activities for work, transport, or leisure during a typical week. Utilising this information, the GPAQ scoring protocol allows for the calculation of weekly metabolic equivalents of tasks (MET) values, with one MET being equivalent to the caloric consumption of 1 kcal/kg/hour. MET values were calculated by multiplying weekly vigorous activity minutes by 8 and moderate-intensity minutes by 4, and a cut-off was applied following recommendations in the GPAQ analysis guide to dichotomise physical activity [
24]. Those who met the following criteria for physical activity for work, during transport and leisure time throughout the week were classified as “sufficiently active”:
i)
At least 150 min of moderate-intensity physical activity OR
ii)
75 min of vigorous-intensity physical activity OR
iii)
An equivalent combination of moderate- and vigorous-intensity physical activity achieving at least 600 MET-minutes per week.
Individuals who did not meet the above criteria were classified as “insufficiently active”.
The GPAQ also contains a single item: “How much time do you usually spend sitting or reclining on a typical day?”, which was used as a measure of sedentary behaviour. Based on two meta-analyses by Chau et al. & Ku et al. [
25,
26], ≥ 7-h/day cut-off was utilised to differentiate between levels of self-reported sedentary behaviour.
Diet screener
The diet screener comprises a list of 30 food/beverage items, that respondents rate on a 10-point scale ranging from ‘never/rarely’ to ‘6 or more times per day’, the frequency at which they consumed a particular food/beverage within the last one year [
27]. The diet screener was interviewer-administered. Standard serving sizes were indicated for each food/beverage item to facilitate this process. Intake frequencies were standardised to a number of servings per day for each food/beverage item. DASH scores were calculated to account for seven intake components: fruit, vegetables, nuts/legumes, whole grains, red and processed meat, low fat dairy, and sweetened beverages. For each of these seven components, participants received a score between 1 and 5 corresponding to the quintile of the intake they fall in, with reverse scoring utilised for meat and sweetened beverages, and these seven quintile scores were summed to form the overall DASH score.
Socio-demographic data on age (18–34, 35–49, 50–64 and 65 and above), sex (Female, Male), ethnicity (Chinese, Malay, Indian and Others), education (Primary and below, Secondary, Pre-U/Junior College, Vocational Institute/ITE, Diploma, Degree, professional certifications and above), marital status (Single, Married/Cohabiting, Divorced/Separated/Widowed), employment (Employed, Economically inactive and Unemployed), and monthly personal income in SGD (Below $2,000, $2,000-$3,999, $4,000-$5,999, $6000-$9,999 and $10,000 and above, and no income) were collected. Further, Body Mass Index (BMI) scores were categorised into four groups based on World Health Organisation guidelines: ‘underweight (< 18.5 kg/m
2), ‘normal range’ (≥ 18.5 kg/m
2 and < 25 kg/m
2), ‘overweight’ (≥ 25 kg/m
2 and < 30 kg/m
2), and ‘obese’ (> 30 kg/m
2) [
28].
Statistical analysis
Survey weights were included in the analysis to account for disproportionate stratified sampling design. The final weights were determined using sampling design weights, non-response adjustment weights and post-stratification adjustment weights. The post-stratification adjustment weights were constructed using ethnicity and age. Unweighted frequencies and weighted percentages were presented for each of the 8-items in the healthy lifestyle nudge questionnaire. To provide the unweighted frequencies and weighted percentages for the acceptance of each nudge, the responses were classified based on the number of related items that the respondents ‘Agreed’ to; the definition of ‘Agreed’ being the indication of either ‘Strongly agree’ or ‘Agree’ for each related item. In addition, the degree of acceptance for each nudge was stratified based on the number of chronic conditions: (i) no chronic condition, (ii) one chronic condition, and (iii) two or more chronic conditions.
To examine the significant correlates of acceptance for each nudge, the responses from the items were reverse coded. Following which, the rating for the related items were added up to obtain a score for each nudge, with higher score indicating greater acceptance to the specific nudge. Using the scores as the outcome variables, multivariable linear regression was performed for each nudge with the following independent variables: age, sex, education, marital status, employment, monthly personal income, BMI, physical activity, sedentary behaviour, and DASH score. Standard errors and significance tests were adjusted for survey weights using Taylor series’ linearisation method. The above analysis was conducted using STATA/SE 17.0 (College Station, Texas), with two-tailed tests assuming 5% significance level.
Conclusion
The study findings indicated that most nudges were generally supported by the respondents, and that most respondents were more approving of less intrusive nudges as a way of promoting healthier lifestyle choices, as is consistent with existing literature. Moreover, both ethnicity and lifestyle choices were found to be associated with the acceptance of certain types of health-nudges and should be taken into consideration by policy makers during the usage and implementation of it in public health policy. For instance, education campaigns can attempt to change beliefs of those with less healthy lifestyles, as those who attribute being overweight tend to show less support for health-related nudges [
47]. As for ethnicity, key opinion leaders and grassroot workers should be engaged to shape culturally appropriate messages and connect with individuals of Chinese ethnicity. However, further research is needed especially in longitudinal cohorts to better understand the impact of nudges on the lifestyle and health outcomes of populations. Health-nudges are not novel in Singapore – efforts such as the HealthHub platform which provides people 24/7 access to their online health records and a wealth of health-related information is one of many examples in a bid to nudge the population towards better health [
48]. Results from the present study highlighting the sort of nudges people are more likely to be accepting of provides up-to-date information which policymakers can utilise to modify ongoing health-nudges if necessary. In the global context, prior studies and reviews have generally reached the conclusion that if people believe that the health-nudge has legitimate goals which fits well with the interests and values of the general public, acceptance are generally high albeit exceptions when other factors such as trust in respective government is lacking. Accordingly, information from the present study may provide certain insights to international counterparts pertaining to the effectiveness of health-nudges efforts in a democratic and multi-ethnic nation like Singapore. Such information may serve as a reference for international counterparts to adapt or implement new health-nudges to better suit their respective population. Taken together, the present study provides up-to-date information on the acceptance of health-nudges in Singapore to better support the design and evaluation of such cost-effective efforts aimed at improving public health.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.