Background
Self-reporting of health outcomes have increasing relevance to research, clinical practice and health planning [
1,
2]. Analysis of quality of life provides complementary information to traditional health indicators based on morbidity and mortality [
3] and it is a valid measurement for self-perceived mental and physical health status that is closely associated with cardiovascular disease and all-cause mortality [
4,
5]. One of the most used instruments worldwide to measure the health related quality of life (HRQL) is the SF-36 questionnaire or its shorter version SF-12 that reduces the administration workload [
3,
4].
Self-perceived health status has been previously associated with diet. Poor diet quality, characterized by low consumption of particular healthy foods or nutrients has been associated with low mental and physical health [
5‐
9]. Furthermore, evidence from dietary intervention studies indicates an improvement of quality of life through healthy diets [
10,
11]. It has been argued that the social and cultural aspects related to the Mediterranean diet may provide additional health benefits [
12]. The PREDIMED study showed in a follow-up period of 4.8 years, that an energy-unrestricted Mediterranean diet which includes consumption of extra-virgin olive oil or nuts resulted in an absolute risk reduction of approximately 3 major cardiovascular events per 1000 person-year, for a relative risk reduction of approximately 30%. These results support the benefits of the Mediterranean diet for cardiovascular risk reduction [
13].
Currently, physical inactivity is a major public health problem [
14]. Exercise reduces mortality and lowers the risk of developing physical and mental chronic diseases [
15]. Studies in the general population [
16‐
19] have found a positive association between physical activity, vitality and mental health. This improves the overall quality of life [
20,
21]. Similar results were found in special populations such as the elderly or the obese [
22,
23].
The subgroup of patients with intermediate cardiovascular risk is the group in which the highest number of cardiovascular events occur [
24], and it is known the association of these with a worse HRQL [
25]. The European Guidelines on cardiovascular disease prevention in clinical practice highlights the importance in those subjects of promoting healthy lifestyle behaviour by tackling unhealthy lifestyles (e.g. poor-quality diet, physical inactivity, smoking) and by optimising risk factors [
26,
27]. Some studies have analyzed the relationship between quality of life, exercise and Mediterranean diet in healthy subjects and individuals with various pathologies but few have focused their research on individuals with intermediate cardiovascular risk. Therefore, the purpose of this study is to analyze the interplay between diet, physical activity and health related quality of life in a Spanish randomly selected sample of individuals attended in general practitioners offices with intermediate cardiovascular risk.
Results
The study population consists of 314 participants with a mean age of 61.1 ± 8.4 years (50.6% women). The main risk factors included 86.6% with dyslipidemia, 75.8% with hypertension, 26.4% with obesity and 24.2% with Type 2 diabetes mellitus. With respect to lifestyle, 167 (53.2%) followed the Mediterranean diet, 78 (24.8%) were sedentary, 68 (21.7%) were current smokers at the time of interview, and 21 (6.7%) were at a high risk level of alcohol consumption. There were gender differences for physical activity and alcohol consumption, in favor of men. All characteristics of the study population are presented in Table
1.
Table 1
Clinical characteristics and lifestyles of the study population
Age (years) | 61.1 | 8.4 | 60.0 | 8.9 | 62.2 | 7.9 | 0.019 |
Hypertension (n, %) | 238 | 75.8 | 122 | 78.7 | 116 | 73 | 0.239 |
Type 2 Diabetes Mellitus (n, %) | 76 | 24.2 | 44 | 28.4 | 32 | 20.1 | 0.113 |
Dyslipidemia (n, %) | 272 | 86.6 | 132 | 85.2 | 140 | 88.1 | 0.509 |
Obesity (n, %) | 83 | 26.4 | 39 | 25.2 | 44 | 27.7 | 0.701 |
Body mass index (Kg/m2) | 28.1 | 4.3 | 28.2 | 3.6 | 28.0 | 4.9 | 0.721 |
Diet |
Adherence to the Mediterranean diet (n, %) | 167 | 53.2 | 75 | 48.4 | 92 | 57.9 | 0.113 |
Mediterranean diet (total score) | 5.5 | 1.5 | 5.4 | 1.5 | 5.6 | 1.5 | 0.243 |
Diet Quality Index (total score) | 31.3 | 2.7 | 31.3 | 2.8 | 31.4 | 2.6 | 0.728 |
Physical activity |
METS-min/week | 1773 | 1703 | 2211 | 2086 | 1346 | 1062 | <0.001 |
Physical activity classification |
Sedentary (n, %) | 78 | 24.8 | 31 | 20.0 | 47 | 29.6 | <0.001 |
Moderately active (n, %) | 90 | 28.7 | 41 | 26.5 | 49 | 30.8 |
Active (n, %) | 71 | 22.6 | 30 | 19.4 | 41 | 25.8 |
Very active (n, %) | 75 | 23.9 | 53 | 34.2 | 22 | 13.8 |
Tobacco |
Smokers (n, %) | 68 | 21.7 | 38 | 24.5 | 30 | 18.9 | 0.273 |
Alcohol |
Grames/week | 73.1 | 109.9 | 116.4 | 134.9 | 30.9 | 50.7 | <0.001 |
Risk consumption (n, %) | 21 | 6.7 | 17 | 11.0 | 4 | 2.5 | <0.001 |
Comorbidities |
Charlson Comorbidity Index | 2.5 | 0.8 | 2.5 | 0.8 | 2.5 | 0.9 | 0.376 |
Table
2 describes the mean scores in the quality of life questionnaire (SF-12). The highest values were obtained in the area of vitality (51.05 ± 11.13), while the lowest were found in the general health (39.89 ± 8.85). For all items, self-perception was greater in men (
p < 0.05) except for the general health and vitality.
Table 2
Health-related quality of life (SF12)
Physical component | 48.36 | 9.29 | 50.05 | 7.55 | 46.71 | 10.48 | 0.001 |
Mental component | 49.47 | 10.48 | 51.36 | 9.74 | 47.64 | 10.88 | 0.002 |
Physical function | 50.69 | 9.04 | 52.53 | 7.90 | 48.90 | 9.72 | <0.001 |
Physical role | 50.92 | 9.20 | 52.59 | 8.19 | 49.29 | 9.85 | 0.001 |
Bodily pain | 49.84 | 11.65 | 53.23 | 9.27 | 46.54 | 12.77 | <0.001 |
General health | 39.89 | 8.85 | 40.63 | 8.51 | 39.16 | 9.13 | 0.142 |
Vitality | 51.05 | 11.13 | 52.16 | 11.18 | 49.96 | 11.01 | 0.080 |
Social functioning | 49.87 | 9.75 | 51.61 | 8.79 | 48.18 | 10.36 | 0.002 |
Emotional role | 48.88 | 9.70 | 50.66 | 9.06 | 47.14 | 10.00 | 0.001 |
Mental health | 49.68 | 10.45 | 52.46 | 10.03 | 46.98 | 10.18 | <0.001 |
The METs-min/week were directly related to the physical and mental component (
r = 0.141,
p < 0.05) (
r = 0.112,
p < 0.05), respectively. This was more significant with physical function (
r = 0.252,
p < 0.01). It was also associated with bodily pain, vitality, as well as emotional and mental health (
p < 0.05, all). The Mediterranean Diet (total score) was related to the mental component (
r = 0.164,
p < 0.01) as well as social functioning (
r = 0.172,
p < 0.01) and vitality (
r = 0.122,
p < 0.05). Moreover, the index of diet quality (DQI) was directly related to the mental component (
r = 0.127,
p < 0.05) and mental health (
r = 0.121,
p < 0.05) (Table
3).
Table 3
Bivariate correlations between health related quality of life and lifestyles
Standardized METSa
| 0.141* | 0.112* | 0.252** | 0.107 | 0.122* | 0.104 | 0.117* | 0.075 | 0.128* | 0.141* |
Mediterranean diet | −0.022 | 0.164** | −0.023 | −0.083 | −0.032 | 0.091 | 0.122* | 0.172** | 0.087 | 0.083 |
Diet quality index | −0.056 | 0.127* | 0.004 | −0.023 | −0.047 | 0.051 | 0.014 | 0.078 | 0.073 | 0.121* |
In the multiple linear regression analysis (Table
4), after adjusting for age, gender, hypertension, dyslipidemia and Charlson Comorbidity Index, we found a 1.177 point increase in the mental component for each increase of 1 point in the Mediterranean diet adherence score (
p < 0.01). Vitality and Social Functioning also kept these associations after the adjustment (β = 0.958 and 0.990, (
p < 0.05 and
p < 0.01), respectively). Furthermore, Mediterranean diet adherence score was inversely associated with Role Physical, regardless of the adjustment variables considered (β = −0.694, (
p < 0.05)). Similarly, for each point of increase in the Diet Quality Index Score, there would be an increase in the mental health of 0.553 and in the mental component of 0.553 (
p < 0.01 and
p < 0.05, respectively). In contrast, after the adjustment, the physical activity was associated with the physical function and vitality (β = 0.090 and 0.087, (
p < 0.01 and
p < 0.05), respectively).
Table 4
Multiple regression analysis of lifestyles health-related quality of life
Mediterranean diet | Physical component | −0.593 | −1.285 | 0.099 | 0.093 | −0,582 | −1.273 | 0.109 | 0.098 |
Mental component | 1.209 | 0.437 | 1.982 |
0.002
| 1,177 | 0.415 | 1.939 |
0.003
|
Physical function | −0.298 | −0.974 | 0.378 | 0.386 | −0.229 | −0.900 | 0.442 | 0.502 |
Role physical | −0.637 | −1.322 | 0.048 | 0.068 | −0.694 | −1.372 | −0.017 |
0.045
|
Bodily pain | −0.508 | −1.378 | 0.363 | 0.252 | −0.499 | −1.339 | 0.341 | 0.243 |
General health | 0.558 | −0.102 | 1.217 | 0.097 | 0.500 | −0.163 | 1.163 | 0.139 |
Vitality | 0.898 | 0.071 | 1.725 |
0.033
| 0.958 | 0.132 | 1.785 |
0.023
|
Social functioning | 1.037 | 0.316 | 1.758 |
0.005
| 0.990 | 0.278 | 1.702 |
0.007
|
Role emotional | 0.540 | −0.183 | 1.263 | 0.143 | 0.527 | −0.192 | 1.245 | 0.150 |
Mental health | 0.612 | −0.168 | 1.391 | 0.124 | 0.572 | −0.179 | 1.324 | 0.135 |
DQIb
| Physical component | −0.175 | −0.556 | 0.206 | 0.366 | −0.223 | −0.607 | 0.161 | 0.254 |
Mental component | 0.583 | 0.158 | 1.008 |
0.007
| 0.553 | 0.129 | 0.977 |
0.011
|
Physical function | −0.017 | −0.388 | 0.354 | 0.929 | −0.042 | −0.414 | 0.330 | 0.824 |
Role physical | 0.034 | −0.343 | 0.412 | 0.858 | −0.055 | −0.433 | 0.323 | 0.774 |
Bodily pain | −0.161 | −0.638 | 0.317 | 0.508 | −0.217 | −0.683 | 0.249 | 0.360 |
General health | 0.275 | −0.086 | 0.637 | 0.135 | 0.242 | −0.126 | 0.609 | 0.197 |
Vitality | 0.159 | −0.297 | 0.615 | 0.493 | 0.186 | −0.275 | 0.648 | 0.428 |
Social functioning | 0.339 | −0.059 | 0.737 | 0.095 | 0.281 | −0.117 | 0.680 | 0.165 |
Role emotional | 0.342 | −0.053 | 0.738 | 0.090 | 0.303 | −0.095 | 0.702 | 0.135 |
Mental health | 0.606 | 0.183 | 1.030 |
0.005
| 0.553 | 0.139 | 0.966 |
0.009
|
METSc-min/week | Physical component | 0.032 | 0.002 | 0.062 |
0.038
| 0.039 | −0.025 | 0.103 | 0.233 |
Mental component | 0.029 | −0.005 | 0.063 | 0.099 | 0.018 | −0.053 | 0.089 | 0.623 |
Physical function | 0.054 | 0.025 | 0.083 |
<0.001
| 0.090 | 0.029 | 0.151 |
0.004
|
Role physical | 0.019 | −0.011 | 0.049 | 0.212 | 0.005 | −0.068 | 0.058 | 0.870 |
Bodily pain | 0.030 | −0.008 | 0.068 | 0.122 | −0.003 | −0.080 | 0.075 | 0.949 |
General health | 0.024 | −0.005 | 0.053 | 0.106 | 0.039 | −0.022 | 0.100 | 0.212 |
Vitality | 0.047 | 0.011 | 0.083 |
0.011
| 0.087 | 0.010 | 0.163 |
0.026
|
Social functioning | 0.015 | −0.017 | 0.047 | 0.354 | −0.009 | −0.075 | 0.058 | 0.793 |
Role emotional | 0.030 | −0.002 | 0.062 | 0.063 | 0.028 | −0.038 | 0.094 | 0.408 |
Mental health | 0.038 | 0.004 | 0.072 |
0.027
| 0.017 | −0.053 | 0.086 | 0.636 |
Discussion
Food habits are related to the mental component of quality of life while physical activity is related to the physical function in a large sample of subjects with intermediate cardiovascular risk. Better food habits—characterized by greater adherence to the Mediterranean diet and a higher score on the diet quality index (DQI)—had the best scores on the mental component, vitality and social function. Likewise, increased physical activity as evaluated with the short Minnesota questionnaire is related to better physical function. To our knowledge, these are the first results that the quality of life is associated with lifestyles related to diet and physical exercise in a sample of adults with intermediate cardiovascular risk. This population has a privileged position to be the target in changing lifestyles that aim at preventing cardiovascular disease and improving quality of life. This relationship (between lifestyles and HRQL) has been shown to exist in other populations but not in subjects with an intermediate CVR [
41‐
43].
Our data indicate that the perceived quality of life could be influenced by physical activity. We found a direct association that occurs for physical and mental components and for the majority of dimensions. However, after adjustment for confounders, only the physical function and vitality maintained statistical significance. These findings are consistent with those published by Kovacs et al. [
17] in elderly women. After participating in an adapted physical activity program, there was a significant increase in the dimensions of physical function and vitality. Similarly, the comprehensive review of Vagetti et al. [
44] indicated a positive association between physical activity and quality of life in the elderly that was consistently associated with functional ability and vitality, among other domains. A cross-sectional study of adults with obesity conducted by Jepsen et al. [
23] prior to a lifestyle intervention showed a significant association with general health. In contrast, a randomized controlled clinical trial of inactive persons [
16] with a program to promote physical activity as an intervention, found no statistically significant changes between the experimental and control group in regard to the quality of life related to health. Other authors have evaluated the quality of life with specific tools for their study population (elderly, obese and patients with cystic fibrosis) [
22,
45,
46]. Similar to our work, they found that physical activity is directly associated with quality of life. Our results would support the idea that physical activity has implications on quality of life related to health to the extent that it might promote individual autonomy through positive changes in dimensions such as the physical functioning.
Our results support the findings of other studies [
42] suggesting a beneficial association of DM with quality of life. However, we include a novelty little studied, the relationship between the quality of food, as measured by the DQI, with the quality of life. The DQI was created to rapidly capture quality of diet based on food intake. Diet quality indexes address the diet’s complexity and are calculated by a combination of foods and/or nutrients with a total score depicting overall diet quality [
47]. In our study population, greater adherence to the Mediterranean diet was associated with higher scores on the SF-12 mental component, social functioning and vitality. Similarly, the diet quality index (DQI) showed an association with the mental component. Adopting a MD in adulthood reduces chronic disease burden and all-cause mortality [
48]. Recent studies show that better adherence to the Mediterranean diet is associated with lower cardiovascular disease [
13], lower risk of metabolic syndrome [
49], better cognitive performance [
50] and has a favourable role on the prevention of colorectal cancer [
51]. These data are consistent with those published by Henriquez Sánchez et al., [
52]. In a cohort study of Spanish university graduates, a positive association was observed between adherence to the Mediterranean diet and vitality (β = 3.38; 95% CI = 1.68–5.07), physical function (β = 2.13; 95% CI = 1.15–3.11) and general health (β = 2.84; 95% CI = 1.16–4.51). Likewise, Bonaccio et al. [
53] showed that adherence to the Mediterranean diet was positively associated with dimensions of mental health (vitality, social function) and physical health (physical functioning, role limitations due to physical and general health), but not pain. Furthermore, Muñoz [
54] included multiple confounders, but still found the same result—adherence to the Mediterranean diet was associated with higher levels of perceived health, both physically and mentally—.
The study by Ruano et al. [
55] compared the quality of life in the Western diet (high consumption of fast food, red meat, and industrial pastry) with the Mediterranean Diet. Values for vitality, mental health, physical functioning, bodily pain and general health were significantly better in the population with greater adherence to the Mediterranean Diet. Moreover, another study published by Ruano et al. [
56], linked the consumption of fat to quality of life and showed a significant inverse association between consumption of saturated fatty acids and the mental dimensions (vitality, social functioning and emotional role) and physical function (physical role and general health). Therefore, our results are in line with previous studies—a greater adherence to the Mediterranean diet is associated with higher scores on the mental dimension in the quality of life questionnaire (SF-12)—.
The main limitation of this study is its cross-sectional design that prevents any causal relationship between quality of life and lifestyles to be analyzed. The design (cross-sectional study) and the questionnaire used to evaluate the adherence to the MD do not allow to assess retrospectively adherence to this dietary pattern nor its temporal association with HRQL. Another limitation is that the quality of life questionnaire used was self-reported. However, this questionnaire has been previously used in studies of similar characteristics.
Acknowledgments
We are grateful to all professionals participating in the MARK study.
Lead author for this group: Rafel Ramos: Research Unit, Primary Health Care, Girona. Jordi Gol Institute for Primary Care Research (IDIAP Jordi Gol), Catalonia, Spain. E-mail: rramos.girona.ics@gencat.net. Coordinating Center: Rafel Ramos, Ruth Martí, Dídac Parramon, Anna Ponjoan, Miquel Quesada, Maria Garcia-Gil, Martina Sidera and Lourdes Camós. Research Unit, Primary Health Care. Jordi Gol Institute for Primary Care Research (IDIAP Jordi Gol). C/Maluquer Salvador, 11. 17002-Girona. Catalonia, Spain. Fernando Montesinos, Ignacio Montoya, Carlos López, Anna Agell, Núria Pagès of the Primary Care Services, Girona. Catalan Institute of Health (ICS), Catalonia, Spain. Irina Gil, Anna Maria Castro of the Primary Care Services, Girona. Institut d’Assistència Sanitaria (IAS), Catalonia, Spain. Fernando Rigo, Guillermo Frontera, Antònia Rotger, Natalia Feuerbach, Susana Pons, Natividad Garcia, John Guillaumet, Micaela Llull and Mercedes Gutierrez of the Health Center Primary Care San Agustín. Ibsalut Balears, Spain. Cristina Agudo-Conde, Leticia Gómez-Sanchez, Carmen Castaño-Sanchez, Carmela Rodriguez-Martín, Benigna Sanchez-Salgado, Angela de Cabo-Laso, Marta Gómez-Sánchez, Emiliano Rodriguez-Sanchez, Jose Angel Maderuelo-Fernandez, Emilio Ramos-Delgado, Carmen Patino-Alonso, Jose I Recio-Rodriguez, Manuel A Gomez-Marcos and Luis Garcia-Ortiz of the Primary Care Research Unit of the Alamedilla Health Center, Salamanca, Spain. Castilla and León Health Service–SACYL.
NSA: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain.
RAD: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Salamanca, Spain.
LGO: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Biomedical and diagnostic sciences department, University of Salamanca, Salamanca, Spain.
CAC: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Salamanca, Spain.
CRM: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Salamanca, Spain.
ACL: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Salamanca, Spain.
BSS: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Salamanca, Spain.
RR: Research Unit Family Medicine, Girona. Jordi Gol Institute for Primary Care Research (IDIAP Jordi Gol), Translab Research Group. Medical Sciences department, School of Medicine, University of Girona, Girona Biomedical Research Institute (IDIBGI), Dr. Trueta University Hospital, Catalonia, Spain.
JAM: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Salamanca, Spain.
MAM: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Medicine department, University of Salamanca, Salamanca, Spain.
JIR: Primary Care Research Unit, The Alamedilla Health Center. Castilla and León Health Service (SACYL), Biomedical Research Institute of Salamanca (IBSAL), Spanish Network for Preventive Activities and Health Promotion (redIAPP), Salamanca, Spain.