Abstract
Objective
To investigate eating habits and adherence to Mediterranean Diet (MD) in relation to the risk of depression in a cohort of nonagenarians enrolled within the Mugello Study, an epidemiological study aimed at investigating both clinically relevant geriatric items and various health issues, including those related to nutritional status.
Design
Cross-sectional study.
Setting
Homes and nursing homes in the Mugello area, Florence, Italy.
Participants
Subjects aged 90-99 years [N=388 (271F; 117M) mean age: 92.7±3.1].
Measurements
All subjects were evaluated through questionnaires and instrumental examinations. Adherence to MD was assessed through the Mediterranean Diet Score. A shorter version of the Geriatric Depression Scale (GDS) was used to detect the possible presence of depressive symptoms. In addition, cognitive and functional status was assessed using the Mini-Mental State Examination, the Clock Drawing Test, as well as the Basic and Instrumental Activities of Daily Living test.
Results
Depressed subjects (DS) (GDS score≥5, 43.8%) were older, females and widows, than non-depressed subjects (NDS). DS reported a slightly but not statistically significant lower MD score than NDS (33.9±3.9 vs. 34.6±3.3, p=0.149). Subjects who reported to consume a greater amount of olive oil and fruit were associated with a lower risk of depression (OR=0.35, 95%CI=0.20–0.59, p<0.001 and OR=0.46, 95%CI=0.26–0.84, p=0.011, respectively) after adjustment for many possible confounders. Similar results were obtained for women, while no statistically significant differences emerged for men.
Conclusion
Our results support the hypothesis that a diet rich in olive oil and fruit, characteristics of MD, may protect against the development of depressive symptoms in older age.
Key words: Nutrition, food, olive oil, fruits, longevity
Introduction
Depression is a highly prevalent psychiatric disorder affecting over 350 million people worldwide (1). It is very common in older adults – especially those affected by medical illnesses (2, 3) – and it is considered to be one of the leading cause of disability contributing to the global disease burden, with serious consequences for both affected individuals and society (4). Late-life depression (LLD) initially occurs after age 65 and is a major public health concern because the elderly who are at high risk constitute an ever-expanding segment of the population. It is characterized by marked sadness, loss of interest or pleasure in daily activities, and may be accompanied by weight change, sleep disturbance, fatigue, difficulty of concentration, and a high suicide rate (5).
Although the etiology of LLD seems to arise from a combination of physiologic effects of aging, physical disabilities, medical illnesses, medications, and psychosocial stress (6), in the last few years growing evidence suggests that diet may play a protective role in the development, progression and treatment of this disease state (7, 8). Indeed, several nutrients resulted to be inversely associated with depression risk, such as folate, omega-3 fatty acids, monounsaturated fatty acids, magnesium, zinc, vitamin B and D (9, 10, 11, 12).
Mediterranean Diet (MD) is certainly the most frequently investigated dietary pattern and it is characterized by large amount of fruits, vegetables, cereals, legumes, nuts, olive oil as the principal source of fat, moderate amount of fish, poultry and dairy products, and low amounts of red meat and wine. Besides the several beneficial effects on chronic degenerative diseases, such as cardiovascular, neoplastic and neurodegenerative diseases (13, 16), adherence to MD has been also inversely associated with depression in several cohort studies (17, 18). In particular, greater adherence to a Mediterranean-based diet has been associated with a reduced number of newly occurring depressive symptoms among older adults (19). However, to the best of our knowledge, no studies investigated the possible influence of MD on depression in very elderly subjects. Thus, the aim of the present study is to investigate the eating habits and the adherence to MD in relation to the presence and risk of depression in a cohort of nonagenarians enrolled on the frame of an epidemiological study conducted in the Mugello area, Tuscany, Italy - namely - the Mugello Study (20).
Materials and methods
Study population
The study population consisted of 388 nonagenarians (117 M, 271 F; mean age: 92.7 ± 3.1 years) enrolled within the Mugello Study. Mugello study is an epidemiological study aimed at investigating some clinically relevant geriatric items, such as functional and cognitive status, along with predictors of their decline, as well as falls and short- and long-term predictors of mortality, but also various health issues including those related to nutritional status. The study protocol has been described in detail elsewhere (20).
Data collection and measurement
Study population was evaluated during a home/nursing home visit through objective examinations and questionnaires concerning lifestyle, dietary habits and cognitive status. General information about demographics, education, personal medical history and use of drugs was collected from each participant. In addition, blood sampling, after overnight fasting, was obtained from each subject.
Adherence to MD was assessed through the Mediterranean Diet Score conceived by Panagiotakos et al (21): for the consumption of items presumed to be close to MD (non-refined cereals, fruits, vegetables, legumes, olive oil, and fish) scores 0 to 5 for never, rare, frequent, very frequent, weekly and daily consumption were assigned, while for the consumption of foods presumed to be away from this pattern (red meat and products, poultry and full fat dairy products) scores on a reverse scale were assigned. Regarding potato consumption, score 5 was given for the recommended intake of 3-4 servings per week, score 4 was assigned for 1-2 servings per week, and scores from 3 to 0 were given for rare, or frequent, very frequent and daily consumption, respectively. Finally, concerning alcohol intake, score 5 was assigned for consumption of less than 3 wine glasses per day, score 0 for consumption of more than 7 wine glasses per day and scores from 4 to 1 for consumption of 3, 4-5, 6 and 7 wine glasses per day. The global score ranged from 0, for a minimal adherence to the traditional MD, to 55 for a maximal adherence.
With regard to the mood profile, a shorter version of the Geriatric Depression Scale (GDS) was used to detect the possible presence of depressive symptoms. The GDS short form is a brief, 15-item questionnaire in which participants are asked to respond by answering yes/no in reference to how they felt over the past weeks. Scores of 0-4 were considered normal, depending on age, education, and complaints; 5-8 indicated mild depression; 9-11 indicated moderate depression; and 12-15 indicated severe depression (22).
Functional disability was assessed using the Basic Activities of Daily Living (BADL) (23) and the Instrumental Activities of Daily Living (IADL) (24) tools. The ability to take a bath, dress, use the toilet, get in and out of bed, defecate, and eat were used to assess the BADL through a 6-item questionnaire, with a total score ranging from 0 (independence in all functions) to 6 (complete dependence). On the other hand, the ability to use the telephone, do shopping, prepare meals, do housework, do laundry, travel, take medicine, and manage finances were used to assess the IADL through a 8-item questionnaire, with a total score ranging from 0 (complete independence) to 8 (complete dependence). In addition, the functional disability was assessed by investigating the patients' walking ability to walk independently, to need walking aids, or to need walking assistance.
Finally, cognitive impairment including participants' memory, orientation, attention and language was assessed by Mini Mental State Examination (MMSE) (25): the global score ranged between 0 and 30 and a score of 23 or below was used to indicate cognitive impairment. In addition, a Clock Drawing Test (CDT) (26), with a global score ranging from 0 (no cognitive impairment) to 10 (prominent cognitive impairment), was used to investigate visuo-constructional abilities and abstract thinking.
Statistical analysis
Statistical analysis was performed using the SPSS (Chicago, IL, USA) software for Macintosh (Version 20.0). Data are reported as mean ± standard deviation (SD), or number and percentage, as appropriate. The non-parametric Mann-Whitney test was used for comparisons between single groups. Kruskal- Wallis test was used for comparisons among different groups. The χ2-test was used to test for proportions.
In order to analyze the possible association between adherence to MD and depression, subjects were categorized into depressed and non-depressed according to the GDS score (scores ≥ 5 were considered indicative of depressive status, whereas scores < 5 were considered indicative of nondepressive status). Logistic regression analysis was performed with GDS≥5 as independent variable and food categories as dependent variables. Variables showing, at univariate analysis, a statistical significant association with depression were introduced in a multivariate model in order to evaluate the association after adjustment for a number of potential confounders and effect modifiers: age (in years); gender; education (years of school); marital status (married, unmarried, widower, cohabitant, divorced); living alone (yes/no); body mass index (BMI); smoking (never smoker, former smoker, current smoker), use of drugs (benzodiazepine, antidepressants, antipsychotics); and a number of self-reported medical conditions (cardio- and cerebrovascular diseases, respiratory diseases, cancer) (yes/no). We also controlled for global cognitive variables according to the scores achieved in MMSE and CDT and for physical disability, assessed using BADL, IADL and walking ability (walking independently, walking with aids, walking with assistance, confined to wheelchair/ bed). Food categories were categorized according to the score obtained at the MDS questionnaire. In particular, high olive oil intake was categorized as dichotomous variables according to the maximum score (5 points), which means daily consumption of olive oil, versus the other scores (0-4 points), meaning not a daily consumption of olive oil. Similarly, fruit consumption was categorized as highest score (5 point, i.e. >18 servings/month) versus lowest scores (0-4 points, i.e. <18 servings/month).
Odds ratio (OR) and 95% confidence intervals (CI) were defined. A p-value < 0.05 was considered statistically significant.
Results
Subject characteristics
Baseline characteristics of the study population according to the presence/absence of depression are shown in Table 1. Depressed (n=170, 43.8%), were significantly older than non-depressed subjects. Females were more prevalent among depressed than among non-depressed. With regard to marital status, widowers were more prevalently depressed when compared to married subjects. No statistically significant difference regarding anthropometric variables, comorbidities or use of drugs of the class of benzodiazepines emerged from the comparison of the two groups, while taking antipsychotics and antidepressants appeared to be more prevalent among depressed subjects. As expected, the analysis of cognitive and functional status highlighted significant differences between the two groups: depressed subjects reported significantly worse score for MMSE, CDT, as well as BADL and IADL with respect to non-depressed. In addition, some differences emerged also from the analysis of walking ability: indeed, a greater number of non-depressed could walk independently, while depressed were more prevalently confined to wheelchair/bed.
Table 1.
Baseline characteristic of the study participants according to GDS
| Study sample | GDS<5 | GDS≥5 | p | |
|---|---|---|---|---|
| (n=388) | (n=218) | (n=170) | ||
| Socio-demographic variables | ||||
| Age, years | 92.7 ± 3.1 | 92.4 ± 3.0 | 93.1 ± 3.3 | 0.031 |
| Females, n (%) | 271 (69.8) | 141 (64.7) | 130 (76.5) | 0.014 |
| Education, years | 4.4 ± 2.8 | 4.6 ± 3.0 | 4.1 ± 2.6 | 0.087 |
| Marital status | ||||
| Single, n (%) | 17 (4.4) | 10 (4.6) | 7 (4.1) | 0.999 |
| Married, n (%) | 72 (18.6) | 51 (23.4) | 21 (12.4) | 0.006 |
| Widow, n (%) | 295 (76.0) | 155 (71.1) | 140 (82.4) | 0.010 |
| Cohabitant, n (%) | 3 (0.8) | 2 (0.9) | 1 (0.6) | 0.999 |
| Divorced, n (%) | 1 (0.3) | - | 1 (0.6) | 0.438 |
| Living alone, n (%) | 87 (24.2) | 55 (26.8) | 32 (20.8) | 0.142 |
| Anthropometric variables | ||||
| Weight, kg | 62.9 ± 12.9 | 63.4 ± 12.5 | 62.4 ± 13.6 | 0.427 |
| BMI (kg/m2) | 25.4 ± 4.7 | 25.4 ± 4.5 | 25.5 ± 4.9 | 0.885 |
| < 18.5, n (%) | 18 (4.9) | 8 (3.8) | 10 (6.5) | 0.337 |
| 18.5 – 24.9, n (%) | 164 (45.1) | 100 (47.6) | 64 (41.6) | 0.120 |
| 25 – 29.9, n (%) | 127 (34.9) | 68 (32.4) | 59 (38.3) | 0.513 |
| ≥ 30, n (%) | 55 (15.1) | 34 (16.2) | 21 (13.6) | 0.382 |
| Lifestyles and medications | ||||
| Smoking habit | ||||
| Never smoker, n (%) | 258 (66.8) | 136 (63.0) | 122 (71.8) | 0.292 |
| Former smoker, n (%) | 119 (30.8) | 76 (35.2) | 43 (25.3) | 0.046 |
| Current smoker, n (%) | 9 (2.3) | 4 (1.9) | 5 (2.9) | 0.513 |
| Drugs | ||||
| Benzodiazepine, n (%) | 68 (17.6) | 37 (17.1) | 31 (18.2) | 0.788 |
| Antidepressants, n (%) | 69 (17.8) | 27 (12.4) | 42 (24.7) | 0.002 |
| Antipsychotics, n (%) | 24 (6.2) | 7 (3.2) | 17 (10.1) | 0.009 |
| Comorbidities | ||||
| Cardiovascular diseases, n (%) | 184 (50.3) | 101 (49.8) | 83 (50.9) | 0.999 |
| Cerebrovascular diseases, n (%) | 88 (24.6) | 46 (23.1) | 42 (26.6) | 0.463 |
| Respiratory diseases, n (%) | 60 (16.8) | 34 (17.1) | 26 (16.5) | 0.999 |
| Cancer, n (%) | 226 (61.1) | 127 (60.8) | 99 (61.5) | 0.999 |
| Cognitive and functional status | ||||
| MMSE score (0-30 points) | 22.8 ± 5.9 | 24.3 ± 5.0 | 20.9 ± 6.5 | <0.001 |
| CDT score (0-10 points) | 4.6 ± 3.5 | 4.0 ± 3.3 | 5.3 ± 3.7 | <0.001 |
| BADL score (0-6 points) | 1.7 ± 2.0 | 1.1 ± 1.6 | 2.5 ± 2.0 | <0.001 |
| IADL score (0-8 points) | 4.3 ± 3.0 | 3.2 ± 2.9 | 5.6 ± 2.6 | <0.001 |
| Walking ability | ||||
| Walking independently, n (%) | 196 (50.5) | 136 (62.4) | 60 (35.3) | <0.001 |
| Walking with aids, n (%) | 117 (30.2) | 58 (26.6) | 59 (34.7) | 0.090 |
| Walking with assistance, n (%) | 28 (7.2) | 12 (5.5) | 16 (9.4) | 0.167 |
| Confined to wheelchair/bed, n | 47 (12.1) | 12 (5.5) | 35 (20.6) | <0.001 |
The p-value for non-parametric variables was calculated with the Mann-Whitney test; the p-value for parametric variables was calculated with the χ2-test.
Adherence to Mediterranean diet
From the analysis of the adherence to MD emerged that the mean overall score was 34.3 ± 3.6; depressed reported slightly lower score than non-depressed, without any statistically significant difference between the two groups (33.9 ± 3.9 vs. 34.6 ± 3.3, p=0.149). Although the adherence score did not show statistically significant gender differences, depressed women reported a significantly lower score than non-depressed (33.6 ± 4 vs. 34.7 ± 3.4, p=0.036, respectively), while no statistically significant differences emerged among men (34.9 ± 3.7 vs. 34.3 ± 3.2, p=0.336, for depressed and non-depressed, respectively).
In order to better clarify the relationship between food pattern and depressive status, data were analyzed by comparing depressed and non-depressed in terms of food intake of the 11-items composing the adherence score (Table 2). Significant differences regarding cereals, fruit and olive oil intake emerged from the comparison of the two groups: in particular, depressed subjects consumed substantially less cereals, fruit and olive oil than non-depressed. By analyzing men and women separately, similar results were obtained also for women, while no statistically significant differences emerged for men.
Table 2.
Number of subjects who achieved a better score (5 points) at the adherence questionnaire, for each Mediterranean diet food category, according to GDS
| Study sample(n=388) | GDS <5 (n=218) | GDS≥5 (n=170) | p | |
|---|---|---|---|---|
| Cereals, n (%) | 355 (91.7) | 205 (94.5) | 150 (88.2) | 0.045 |
| Potatoes, n (%) | 6 (1.6) | 3 (1.4) | 3 (1.8) | 0.100 |
| Fruit, n (%) | 334 (86.3) | 196 (90.3) | 138 (81.2) | 0.018 |
| Vegetables, n (%) | 251 (64.9) | 147 (67.7) | 104 (61.2) | 0.239 |
| Legumes, n (%) | 4 (1.0) | 1 (0.5) | 3 (1.8) | 0.323 |
| Fish, n (%) | 2 (0.5) | - | 2 (1.2) | 0.191 |
| Read meat, n (%) | 27 (7.0) | 15 (6.9) | 12 (7.1) | 0.100 |
| Poultry, n (%) | 21 (5.4) | 12 (5.5) | 9 (5.3) | 0.100 |
| Dairy products, n (%) | 24 (6.3) | 11 (5.2) | 13 (7.7) | 0.396 |
| Olive oil, n (%) | 310 (80.9) | 191 (88.0) | 119 (71.7) | <0.001 |
| Alcohol, n (%) | 279 (72.7) | 131 (78.0) | 148 (68.5) | 0.051 |
The p-value was calculated with the χ2-test.
In an attempt to clearly depict the nature of the association between adherence to MD and depressive symptoms, logistic regression analysis was performed in order to test the possible association between food categories' consumption and risk of depression. Among the 11-items of the score, only olive oil and fruit intakes resulted to be associated with the risk of LLD. In particular, participants with the highest olive oil consumption (5 points, i.e. daily consumption) reported a lower risk of depression (model 1: OR=0.34, 95%CI 0.20 – 0.59, p<0.001) with respect to those reporting a lower frequency of consumption. The association progressively weakened, but remained statistically significant also after adjustment for additional confounders, resulting even stronger after adjustment for all the possible confounders (model 5: 0.35, 95%CI 0.18 – 0.67, p=0.002) (Table 3). Similarly, participants who reported a high fruit intake (5 points, i.e. >18 servings/ month) demonstrated to have a lower risk of depression (model 1: OR=0.46, 95%CI 0.26 – 0.84, p=0.011) when compared to those reporting a lower frequency of consumption. The association remained statistically significant also after adjustment for demographic variables, use of drugs and cognitive variables (model 4: OR=0.47, 95%CI 0.24 – 0.92, p=0.028), losing however its significance after additional adjustment only for functional variables (Table 3).
Table 3.
Logistic regression analyses for the risk of having depression according to olive oil (daily vs. not daily) and fruit intake (>18 servings/months vs.<18 servings/month)
| Variable adjustment | OR | Olive oil 95% CI | p | OR | Fruit 95% CI | p |
|---|---|---|---|---|---|---|
| Model 1* | 0.34 | 0.20 – 0.59 | <0.001 | 0.46 | 0.26 – 0.84 | 0.011 |
| Model 2° | 0.35 | 0.20 – 0.60 | <0.001 | 0.48 | 0.26 – 0.89 | 0.015 |
| Model 3§ | 0.38 | 0.22 – 0.66 | 0.001 | 0.49 | 0.26 – 0.90 | 0.022 |
| Model 4^ | 0.39 | 0.22 – 0.71 | 0.002 | 0.47 | 0.24 – 0.92 | 0.028 |
| Model 5| | 0.35 | 0.18 – 0.67 | 0.002 | 0.58 | 0.28 – 1.20 | 0.142 |
* Model 1: crude model; ° Model 2: adjusted for model 1 and for age, gender, and marital status; § Model 3: adjusted for model 2 and for antidepressants and antipsycothics; ^ Model 4: adjusted for model 3 and for Clock Drawing Test and Minimental State Examination; | Model 5: adjusted for model 4 and for BADL, IADL and walking ability
Furthermore, data were analyzed separately for men and women, in order to investigate any possible association between food categories' intake and depression, according to gender. Women showed similar results to those of the general population after adjustment for all confounders, both for olive oil and fruit intake (OR=0.33, 95%CI 0.15 – 0.69, p=0.003 for olive oil and OR=0.34, 95% CI 0.14 – 0.86, p=0.023 for fruit intake), while no statistically significant associations were found among men.
Discussion
To the best of our knowledge, the present is the first study that examined the association between dietary habits and risk of depression in very elderly (>90 years) subjects. In line with the literature (3, 4) the results obtained from this study confirm that particular conditions such as age, gender, marital status, physical and cognitive status are associated with depression. Moreover, in this study sample, we were able to observe that dietary habits may protect against the development of depressive symptoms in older age. In particular, a diet rich in olive oil and fruit, characteristics of the Mediterranean dietary pattern, seems to protect against the risk of depression. This result seems to be particularly evident among women.
The first important aspect emerged from our study is the higher percentage of depressed subjects, in comparison with other studies that investigated depression in the elderly (27, 28). This could be explained by the fact that we enrolled exclusively nonagenarians, and this leads us to consider that the incidence of depression has a strong correlation with age. Indeed, the elderly represent a particular portion of the population, in which the simultaneous presence of comorbidities and physiological cognitive decline, as well as functional impairment, may lead to a higher incidence of depression, due to an increased isolation and vulnerability. Even the marital status plays a crucial role in the development of depression; indeed, some cross-sectional studies (29, 30) highlighted that depressive symptoms are more frequently expressed among widowed, with respect to married subjects, due to a poorer psychological well being, closely related to loneliness (31). Moreover, consistent with previous studies (32-34), our findings show that the prevalence of depression was higher in women than men. This could be related to the fact that in our sample women were older than men, thus having worse physical and cognitive status, but it can also depend from both biological (e.g. variation in ovarian hormone levels) (32, 33) and social gender differences (e.g. women are more sensitive to adversities experienced by their network) (34).
In the last few years growing evidence suggests that also eating habits may be related to the development, progression and treatment of depression (7, 8). The strong inverse association between olive oil intake and risk of depression we found in our study sample – and especially among women – could be linked to the high content of mono-unsaturated fatty acids, e.g. oleic acid, from which the lipid oleamide can be biosynthesized. Oleamide presents an important role related to mood disorders, such as the induction of sleep (35). It also plays a role in the maintenance of the physico-chemical properties of membranes due to its ability to increase the delta-9 desaturase enzyme activity, so improving the binding of serotonin to its receptors (36, 37). In addition, olive oil contains some bioactive polyphenols with important anti-inflammatory properties that could improve the function of the endothelium (38). Finally, the antioxidant actions of extra virgin olive oil components such as tyrosol are capable to restore the intracellular antioxidant defenses (39), which result decreased among depressive patients (40).
According to the observation that oxidative stress and inflammation are connected to the pathophysiology of depression, our sample showed that depressed nonagenarians reported a lower fruit intake than non-depressed. The most accepted hypothesis to explain the protective effect of fruits is the combination of fibers and antioxidant components, such as vitamins C and E, carotenoids, and other bioactive components, like flavonoids (41). The potential effect of fruit antioxidants involves the suppression of inflammation and injury of neuronal cells, and the promotion of cognition (42), while dietary fibers directly influence intestinal microbiota, which again appear to influence the development of neurotransmitter brain systems and modulate affective and stress-related disorders and depressive behavior (43).
In several prospective studies an unhealthy western dietary pattern – rich in sweetened beverage, refined food, fried food, processed meat and high fat intake – was associated with an increased prevalence of depression (44, 45). On the other hand, Mediterranean diet as well as other healthy diets characterized by a large amount of olive oil, fish, fruits, vegetables, nuts, legumes, and moderate amount of poultry, dairy and unprocessed meat have been inversely associated with depression risk, due to the high number of dietary constituents such as antioxidant nutrients, dietary fiber and fat composition. (17-19). The nonagenarians of our sample showed an overall good adherence to the Mediterranean diet, regardless of presence of depression. In addition, although the adherence score did not show statistically significant gender differences, depressed women reported a significantly lower score than nondepressed, while no statistically significant differences emerged among men.
This study has some limitations. First of all, the self-reported subjective GDS questionnaire that was used for defining depressive symptoms can be a limitation because it relies on self-reported answers without a clinical diagnosis of depression. However, the questionnaire has been validated extensively and shows good validity. Moreover, a self-report memorybased method to obtain dietary information can be considered as a limitation. The study population mainly consisted of older individuals and the possibility that imprecisions on dietary recall, due to poor cognitive functioning, attenuated the association can not be fully excluded. Finally, the present is a cross-sectional study, that presents different limitations due to the nature of the study. Only prospective randomized controlled studies can confirm these observational results.
However, several strengths of our study also deserve to be mentioned, such as the peculiar study sample composed of very elderly subjects never analyzed before, the multiple adjustments of our estimates for potential confounders and the existence of published validation studies of our methods. An additional strength is related to the analyses of the single food categories composing the Mediterranean diet, rather than the only Mediterranean Diet Score. Indeed, it is possible that adoption of a healthy diet is related to other healthy lifestyle factors – e.g. less smoking habit and more physical activity – responsible for the lower risk of depression.
Conclusions
We found that greater consumption of olive oil and fruit, characteristic of a Mediterranean-based diet, was associated with lower likelihood of depressive symptoms in very elderly subjects, especially in women. Although the exact mechanism for this association is unclear, our study provides further evidence that adopting a healthy diet in older age confers many benefits, including protection against depressive symptoms.
Conflict of Interest
The authors report no conflict of interest.
Author Contributions
Conception and design: GP, FS, SC, FV, CM; Analysis and interpretation of the data: FV, RML, FS; Drafting of the article: GP, FS, SC, CM; Clinical evaluation of patients: GuP, FC; Critical revision of the article for important intellectual content: SS, CM; Final approval of the article: CM; Statistical expertise: FV, CML, FS.
Sponsor's Role
The study was not funded.
* The Mugello Study Working Group also includes Roberta Boni, Chiara Castagnoli, Annamaria Gori, Maria Luisa Eliana Luisi, Anita Paperini, Lorenzo Razzolini, Nona Turcan, Debora Valecchi, Gianfranco Gensini, and Rosanna Abbate.
Giuditta Pagliai
no disclosures to report; Francesco Sofi: no disclosures to report; Federica Vannetti: no disclosures to report; Simona Caiani: no disclosures to report; Guido Pasquini: no disclosures to report; Raffaello Molino Lova: no disclosures to report; Francesca Cecchi: no disclosures to report; Sandro Sorbi: no disclosures to report; Claudio Macchi: no disclosures to report.
Ethical standard
The present study followed the ethical guidelines of the Declaration of Helsinki and was approved by our departmental Ethics Committee.
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