Italian Psychometric Validation of the Multidimensional Students’ Health-Promoting Lifestyle Profile Scale

The present study examines the factorial structure and assesses the psychometric properties of the adapted multidimensional Health-Promoting Lifestyle Profile II Scale, considering a sample of Italian university students who participated to an online survey. The original 52-items Scale showed a high overall internal consistency. Four of the six subscales were associated with good values of the Cronbach’s α coefficient, whereas two subscales had lower values. Hence corrected item-total correlation was calculated and 26 items that decreased the scale’s reliability were deleted. The remaining 26 items were first subjected to Principal Component Analysis that suggested a conceptually meaningful five-factor model. This result was further supported by the first-order confirmatory factor analysis, in which all the factor loadings were statistically significant. The internal consistency and the composite reliability for the reduced version of the Scale and its subscales have shown a good reliability for the measurement models. The multidimensionality of the scale was also confirmed by a second-order factor model.


Introduction
The World Health Organization (WHO) has defined the concept of health as "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity" ( [1] p. 100). WHO references the bio-psycho-social person's current health status, it will also have long-term health consequences.
It is well known that young people often engage in a wide range of unhealthy habits in terms of nutrition and exercise, and/or participate in illicit behaviors, such as the use of substances (e.g., alcohol, tobacco, and drugs). This can lead to adverse health outcomes, and it can put them at long-term high risk for serious health problems later in life, such as cardiac, respiratory, metabolic, degenerative, and psychiatric diseases and cancer [11]. These unhealthy habits have a negative impact on health, and it is important to emphasize health-promoting practices and psychosocial well-being to the current generations of children, adolescents, and young adults.
Cultural, social, and economic aspects are very important when defining well-being. The scientific literature describes the Italian young adult context as being "characterized by uncertainty-towards the future, personal relationships and professional status (…) and resignation-accepting the status quo without striking forms of protest, dissent or rebellion" ( [12] p. 1). Vancea and Utzet [13] have suggested that young people are especially vulnerable to health problems if they are unemployed or working in precarious conditions. In Italy, there is "the crisis" for young people due to the economic conjuncture [14] and the lack of trade union support and/or political representation [15].
Many researchers have suggested "that the rapid expansion of insecure contractual arrangements in the 1990s-early 2000s have produced increasing difficulties in terms of transitions to a "better" job condition (i.e., into secure employment), which enhanced the role of the family of origin in overcoming them, generating new inequalities among young Italians" ( [16] p. 1). In fact, in Italy, many young adults live with their parents; thus, they are not independent in terms of the psychological, social, and economic aspects related to health and well-being. This situation is often associated with stress in the transition to adulthood [17] [18].
Many studies have used the multidimensional HPLP-II scale in a university setting [19]- [24]. However, to the best of our knowledge, this instrument has never been used among a study population of Italian students. Thus, the use of the HPLP-II Scale could be relevant for the prevention and for the intervention.
In the following, the Scale is used to assess the wellness dimensions of Italian university students, starting from findings reported in previous studies.

Procedure
The study was designed and performed in accordance with the Declaration of Helsinki. The protocol included a full assurance of anonymity, participation discretion, and the absence of risk, burden, sponsors, conflicts of interest, and incentives for the responding participants. The appropriate ethical committee approved the protocol. Implied consent was obtained, because the questionnaire was administered through an electronic tool (each questionnaire has been filled one time based on IP address), which the students had to specifically and intentionally access on the Internet. Nevertheless, a disclaimer text indicated the aim of the study, and the anonymous and voluntary nature of participation was presented in the header of the web page questionnaire.
The data were collected from an online questionnaire using Research Electronic Data Capture (REDCap), an electronic data capture tool [25] hosted by the university. REDCap is a secure, Internet-based application designed to support data capture for research studies. It provides: 1) an intuitive interface for validated data entry; 2) audit trails for tracking data manipulation and export procedures; 3) automated export procedures for seamless data downloads to common statistical packages; and 4) procedures for importing data from external sources. The online questionnaire used retained the structure of the original questionnaire, and was easily writable and editable using a PC or a tablet or a smartphone. Face validity of the questionnaire was assumed, because it had already been used for studies in the same setting of University students in many different countries.

Participants
The target population of the study was university students in southern Italy enrolled in an undergraduate program. A self-selected sample of students was employed, and the participants were recruited by placing posters in the rooms in the student union on campus. Moreover, the students were invited to participate through the student union's social network webpages. The instrument to collect data was an anonymous, self-reported online questionnaire in which the only requested socio-demographic characteristics were age and gender. tive gender identity (e.g. subjects who identified themselves as homosexual) (see Table 1). The respondents have an age ranged from 18 to 35, with a mean age of around 23 (SD = 3.09).

Instruments
The multidimensional HPLP-II Scale was used to conduct the present study by considering "the theorized dimensions of a health-promoting lifestyle" [4] [9].
The original version of this instrument includes 52 items (Appendix B) categorized into six subscales [9]. The following dimensions were investigated: • Health Responsibility (HRESP) [9 items]: taking responsibility for one's own well-being; attending to and educating oneself with regard to health; using informed consumerism when seeking professional care; The items ask a respondent to indicate how often he/she adopts specific health-promoting behaviors or well-being habits. The items are scored on a 4-point Likert scale: "never" (1), "sometimes" (2), "often" (3), and "routinely" (4).
The original HPLPII [9] was assessed in 712 adults ranging from 18 to 29. Content validity was established by literature review and experts' evaluation, construct validity was supported by factor analysis that confirmed a six-subscale structure and reliability was measured by α coefficient, which was 0.94 for the total scale and ranged from 0.79 to 0.87 for the subscales. Taking into account the peculiarity of socio-cultural factors in each nation, some authors have reported interesting results on the use of this scale in university setting. In Spain, Pérez-Fortis et al. [21] found that a six-factor model of a 44-item scale accounted for 40% of the variance, and the scale had an internal consistency of 0.87. In Jordan, Alkhawaldeh [23] found that the total average score of the HPLP-II Scale for students was 2.4 (Standard Deviation [SD] = 0.4).
The highest mean score was for the spiritual growth dimension (Mean = 3.0, SD = 0.7), and the lowest mean score was for the physical activity dimension (Mean = 2.0, SD. = 0.7). In Portugal, Sousa et al. [24] found an adequate fit to a 52-item scale with a six-factor structure in a cross-cultural study. They reported a global Cronbach's α coefficient of 0.93. In Turkey, Pinar et al. [19] studied adults and found Cronbach's α coefficients greater than 0.70 for the six dimensions. After performing tests on the latent construct measurement, the final model reduced the number of items from 52 to 48. In Taiwan, Meihan and Chung-Ngok [20] validated the HPLP-II Scale and obtained a total Cronbach's α coefficient greater than 0.70 for the revised instrument; the values for the six dimensions ranged from 0.71 to 0.91. In Japan, Wei et al. [22] found a mean of 2.5 (SD = 0.29), the highest mean was associated with the interpersonal relationships dimension, and the lowest mean was associated with the health responsibility dimension.

Analysis
The multidimensional HPLP-II Scale was evaluated for its reliability and validity. Internal consistency was considered to assess the reliability of the results across items within the adopted scale by using Cronbach's α coefficient. For internal validity, a two-step procedure was performed to confirm the factor structure of the scale by means of exploratory factor analysis (EFA), and confirmatory factor analysis (CFA) [26], as reported in other studies in different theoretical frameworks (e.g., [27] [28] [29] [30]).
According to the procedure discussed in Bai et al. [31] and Bozkurt et al. [32], the total sample of 517 participants was randomly divided into two sample groups (Sample 1 with n = 193, around 40% of the survey participants; Sample 2 with n = 324, around 60% of the survey participants) using the Statistical Package for the Social Sciences (SPSS) random case selection function. This procedure ensured that the EFA sample was not the same as the CFA sample, and then the sample findings could be generalized to the population. Item analysis and EFA were conducted on Sample 1. EFA analysis was performed using principal component analysis (PCA) with Varimax rotation implemented in the SPSS. For Sample 2, a first-order CFA model was used to explore the validity of the factor solution identified in the exploratory step; a second-order CFA model was specified to prove that the items were multidimensional in line with the suggestions presented in Walker et al. (1987) seminal paper. The CFA analyses were conducted with R software using the Lavaan package [33] for the model estimation and the semPlotpackage [34] for the graphical representation of the measurement models. To minimize the loss that occurs in list wise deletion, a pair wise deletion (available-case analysis) was adopted in the exploratory and confirmatory factor analyses, assuming that missing answers were completely random.

Exploratory Analysis
Starting from the information provided by the sample of 517 participants, the descriptive statistics for the each subscale and the total scale are presented in subscale, the kurtosis value was higher than 3, indicating deviations from the normal distribution. Thus, those items were removed (in our opinion the determinants of this phenomenon are found in the student cultural variation, as we will discuss in the concluding section).
Internal consistency was assessed for the entire instrument as well as for each subscale. The HPLP-II Scale showed a high overall internal consistency: the Cronbach's α coefficient for the total 52-item scale was 0.90 (see Table 3), which is near the original value of 0.92 for the English language version reported [9]. Corrected item-total correlation was calculated for the total scale and for the six subscales.
Step-by-step, the items that decreased the scale's reliability were deleted. A total of 26 items was deleted from the instrument on the basis of the item analysis findings. More specifically, the following items were not included in further analysis: hplp_09, hplp_21, hplp_33, hplp_45, and hplp_51 from the HRESP subscale; hplp_34 from the PHACT subscale; hplp_14, hplp_32, hplp_38, and hplp_50 from the NUTRI subscale; hplp_18, hplp_48, and hplp_52 from the SPGROW subscale; and hplp_07, hplp_37, hplp_43, and hplp_49 from the INTRE subscale. All the items related to the STMAN subscale were disregarded given their poor inter-item correlations and low α coefficient value. A description of the specific items is presented in Appendix B.
The remaining 26 items were first subjected to EFA. Specifically, PCA using a Varimax rotation with Kaiser Normalization was performed. The scree plot, with Kaiser's "greater than one" criterion [35] was used to determine the number of factors to be retained. A first solution with six factors was obtained. Nevertheless, the examination of this factorial solution showed that the NUTRI subscale items were split into two factors. Hence, a five-factor solution was estimated by fixing the extracted factors to five. This approach is supported by pre-Health vious results that explored the dimensionality of the HPLP-II Scale in which the items were included in a unique dimension. The results of the Kaiser-Meyer-Olkin (KMO = 0.80) test and Bartlett's test of sphericity (χ 2 = 1777.53, p < 0.001) obtained from this latter solution demonstrate the adequacy of the sampling in which the criteria for conducting a factor analysis were met.
The final five-factor solution (see scree plot in Figure 1 and the items' factor loadings and communality values in Table 3) shows a clear, interpretable structure accounting for 55.53% of the total variance (specifically, Factor 1: 22.18%; Factor 2: 12.55%; Factor 3: 8.46%; Factor 4: 6.98%; and Factor 5: 5.36%). The first factor captured the PHACT subscale, the second factor captured the SPGRO subscale, the third factor captured the HRESP subscale, the fourth factor captured the INTRE subscale, and the fifth factor captured the NUTRI subscale.
The communalities (see Table 3) of most items were greater than or close to 0.50 (except for the item hplp_46 and for other items with values close to 0.40), which indicated that this factor solution adequately accounted for almost all variables [36].

Confirmatory Factor Analysis
As a second step, CFA was conducted to confirm whether the emerging five-factor solution was consistent with the model suggested by the PCA in the exploratory analysis.
Correlations between the five factors showed statistically significant coefficients G. Savarese et al. In addition, a second-order CFA model was estimated in line with the conceptualization advocated in Walker et al. [8] to test the hypothesis that a higher order factor (HPLP-II) represents the pattern of relations among the first-order factor model [42]. In this way, higher-order CFA enables one to test the multi- to the data than the first-order factor model (see Figure 2 and Figure 3). To compare the two models, the chi-square difference test was used to determine which model was better (Δχ 2 = 649.09 -585.34 = 63.75, Δdf = 5, p <0.001). The null hypothesis (the two models are identical), was rejected: the first-order factor model is better than the second-order factor model. Hence, it seems that the higher-order CFA did not support the unidimensionality of the data, and the five dimensions solution of the first-order CFA was confirmed.
Finally, the internal consistencies (Cronbach's α) and composite reliability (CR, ω coefficients) for the HPLP-II Scale and its subscales in the first-order factor model and the second-order factor model at Level 1 and Level 2 are listed in Table 4. Both criteria show good reliability for the measurement models with

Discussion
The present study validated the HPLP-II Scale using a sample of 517 Italian university students. The HPLP-II Scale was found to have good overall internal consistency for four of the six subscales, which is in line with the results reported in previous studies.
The adapted 26-item HPLP-II Scale solution with five dimensions was supported by both analyses, EFA and CFA. The first-order CFA model presented an adequate fit to the data on Italian university students. However, in contrast to the results reported by Walker et al. [8], in which second-order CFA yielded a single factor interpreted as a health-promoting lifestyle, in the present study the multidimensionality of the scale was confirmed.
Half of items of the total scale were disregarding in the revised version of the instrument thanks to the item analysis conducted in the exploratory phase. A review of the item statistics as well as a consideration of the meaning of these items within the cultural context of Italy (specifically the country's young population) led to the decision that, in this framework, the 26-item Italian version of the HPLP-II Scale was the most appropriate version and there was no effect on content validity of the original version of the questionnaire.
The psychological well-being is a state of equilibrium between an individual and the physical and social/cultural environment in which he/she lives [43]. A previous study [44] reported that the Italian young adults need to develop adequate competencies on the cognitive, emotional-affective and strategic behavior-al levels, but their coping strategies are mainly those that involve emotions more than cognition. Furthermore, the Italian socioeconomic context offers too few opportunities for members of this population. This socio-economic and professional uncertainty results in a negative relationship between internal coping and the many ineffective strategies employed to reduce perceived stress [45] [46] [47] [48] More specifically, the STMAN subscale was omitted from the additional analysis. In the literature, stress management includes optimism, flexibility, and stress tolerance [49]. Generally speaking, the modern working environment (which is often uncertain for young adults) increases chronic stress and results in insufficient coping behaviors [50]. In Italy, due to the alarming work crisis, the cultural variation on emotional response [51], and the domain of dependence upon parents [52], young adults probably do not possess the resources that may help them manage stress.

Conclusions
In conclusion, the results indicate that the HPLP-II Scale seems to be a valuable tool for studying representations of the promotion of well-being and lifestyle, and its Italian version could be applied to the Italian population as a tool to evaluate a health-promoting lifestyle. The final five-factor solution for the Italian version is composed of 26-item with an interpretable structure. Cronbach's α values are greater than 0.70 (except for the INTRE subscale) and composite reliability values greater than 0.06. From the interpretation of the statistical results, the stress management subscale, as well as some of the items from the other subscales, did not help young adults identify the psychological and physical resources that need to be activated to effectively control or reduce stress and, in general, enhance different factors related to well-being and lifestyle.
Finally, caution is merited, given that the present study is limited to a self-selected sample of university students at a single university. The generalizability of its findings is not allowed. Further analyses are needed to validate the HPLP-II Scale in a larger sample and to compare the results across people of different ages offering a wide representation of the Italian socio-economic and cultural environment. However, if the findings were confirmed by further analysis in different settings, the HPLP-II Scale could be used to monitor the psychological and behavioral changes of young people related to a health-promoting lifestyle during their educational years; the scale could also be used to evaluate the effectiveness of ad hoc university programs devoted to improving students' health-promoting lifestyles.

Conflicts of Interest
The authors declare no conflicts of interest regarding the publication of this paper.