Nature-based social interventions to address loneliness among vulnerable populations: a common study protocol for three related randomized controlled trials in Barcelona, Helsinki, and Prague within the RECETAS European project

BACKGROUND

The negative effects of loneliness on population health and wellbeing requires interventions that transcend the medical system and leverage social, cultural, and public health system resources. Group-based social interventions are a potential method to alleviate loneliness. Moreover, nature, as part of our social and health infrastructure, may be an important part of the solutions that are needed to address loneliness. The RECETAS European project H2020 (Re-imagining Environments for Connection and Engagement: Testing Actions for Social Prescribing in Natural Spaces) is an international research project aiming to develop and test the effectiveness of nature-based social interventions to reduce loneliness and increase health-related quality of life.

METHODS

This article describes the three related randomized controlled trials (RCTs) that will be implemented: the RECETAS-BCN Trial in Barcelona (Spain) is targeting people 18+ from low socio-economic urban areas; the RECETAS-PRG Trial in Prague (Czech Republic) is addressing community-dwelling older adults over 60 years of age, and the RECETAS-HLSNK trial is reaching older people in assisted living facilities. Each trial will recruit 316 adults suffering from loneliness at least sometimes and randomize them to nature-based social interventions called "Friends in Nature" or to the control group. "Friends in Nature" uses modifications of the "Circle of Friends" methodology based on group processes of peer support and empowerment but including activities in nature. Participants will be assessed at baseline, at post-intervention (3 months), and at 6- and 12-month follow-up after baseline. Primary outcomes are the health-related quality-of-life according to 15D measure and The De Jong Gierveld 11-item loneliness scale. Secondary outcomes are health and psychosocial variables tailored to the specific target population. Nature exposure will be collected throughout the intervention period. Process evaluation will explore context, implementation, and mechanism of impact. Additionally, health economic evaluations will be performed.

DISCUSSION

The three RECETAS trials will explore the effectiveness of nature-based social interventions among lonely people from various ages, social, economic, and cultural backgrounds. RECETAS meets the growing need of solid evidence for programs addressing loneliness by harnessing the beneficial impact of nature on enhancing wellbeing and social connections.

TRIAL REGISTRATION

Barcelona (Spain) trial: ClinicalTrials.gov, ID: NCT05488496. Registered 29 July 2022. Prague (Czech Republic) trial: ClinicalTrials.gov, ID: NCT05522140. Registered August 25, 2022. Helsinki (Finland) trial: ClinicalTrials.gov, ID: NCT05507684. Registered August 12, 2022.

"The sarcoidosis map": a joint survey of clinical and immunogenetic findings in two European countries

We pooled immunogenetic data obtained in independent studies in two European populations (Italian and Czech) of patients affected by sarcoidosis. Correspondence analysis was used to investigate the associations between clinical and immunogenetic data. Two hundred and thirty-three patients were enrolled in the study, of which 126 were from the Czech Republic and 107 from Italy. Using a common protocol, we examined each patient for sex, age of disease onset, roentgenologic stage, extrapulmonary spread, and clinical course. One thousand and ten healthy individuals, HLA typed for class I and II serologic polymorphisms, served as controls. Findings that were essentially in agreement in both populations were: (1) a positive association of sarcoidosis with HLA-A1, B8, and DR3 markers, and a negative association with HLA-B12 and DR4; (2) a prevalence of HLA-DR3 and DR4 among females and of DR5 among males; (3) a relationship of B13 and B35 with early onset and of A30, B8, DR3, and DR4 with late onset of disease; (4) an association of B27 with sarcoidosis restricted to the lungs; (5) a relationship of A1, B8, B27, and DR3 to roentgenologic stage I and of B12 and DR4 to stage III; and (6) an association of HLA-DR3 with a good outcome. Population-restricted findings essentially concerned the alleles HLA-B13 and B22, the former being associated with the disease, male sex, early onset, extrapulmonary localization and relapse only in Czechs, and the latter to disease spread only in Italians. Our results seem to support the concept that immunogenetic background may at least partly account for the clinical heterogeneity of sarcoidosis.

Polymorphism of the 5' flanking region of the HLA-DQA1 gene in coeliac disease

Coeliac disease (CD) is associated with particular HLA genotypes. The susceptibility gene (or genes) has been mapped to the class II region, most probably to the DQ loci. Polymorphism of the upstream promoter region of the DQA1 gene (QAP) has been recently reported. At least ten variants or QAP alleles have been found, some of which are present in the cis-acting regulatory sequences. Allelic differences in DQ molecule expression may play a role in susceptibility to CD. We investigated the QAP polymorphism in 102 CD patients and 142 unrelated healthy controls of Czech origin using polymerase chain reaction amplification (PCR) of genomic DNA and oligonucleotide probes. We found a significant frequency increase of the alleles QAP 4.1 (RR = 10.3, p.c. = 10(-6) and QAP 2.1 (RR = 2.4, p.c. = 0.017) in patients over controls. An increased susceptibility is provided by the presence of both alleles, as is shown by the higher proportion of QAP 4.1, 2.1 heterozygotes among patients than expected from the Hardy-Weinberg equilibrium and by the comparison of the odds ratios for these alleles. There is a strong linkage disequilibrium between the QAP alleles and the DQA1, DQB1, and DRB1 loci. Two haplotypes carrying the QAP alleles whose frequency is increased are predominant in this group of CD patients: DQB1*0201, DQA1*0501, QAP4.1, DRB1*0301 and DQB1*0201, DQA1*0201, QAP 2.1, DRB1* 0701. Thus, the QAP variants are increased as part of these haplotypes and we cannot discriminate if they are responsible for the primary association.

Effect of delta9-tetrahydrocannabinol on mitochondrial NADH-oxidase activity

Delta9-Tetrahydrocannabinol (delta9-THC), the active ingredient of marihuana was found to be a highly effective inhibitor in vitro of the NADH-oxidase activity of rat brain and heart mitochondria. The degree of inhibition of the enzyme system obtained from rat brain tissue varied with the region from which it was derived as follows, in the presence of 10(-5) M delta9-THC: hypothalamus plus thalamus plus midbrain, 73 +/- 4%; cerebellum, 66 +/- 4%; medulla oblongata plus pons, 63 +/- 6%; cerebral cortex, 50 +/- 8%. The same concentration inhibited rat heart NADH-oxidase activity 69 +/- 9%. Inhibition of NADH-oxidase activity by a corresponding concentration of deoxycorticosterone was significantly less in all tissue preparations tested, ranging from 11% to 26%. The inhibition of delta9-THC appeared to be competitive and near the amytal-sensitive site of the electron transport system. Suggestive evidence was also obtained for a second site of action, above the cytochrome c site.

Hypertensive action of 18-hydroxydeoxycorticosterone

18-Hydroxydeoxycorticosterone is an adrenal steroid hormone causing salt and water retention and is secreted in greatly increased amounts in response to the pituitary hormone adrenocorticotropic hormone. Its production is abnormally high in some forms of hypertension in man and rat. Direct proof that 18-hydroxydeoxycorticosterone is capable of causing hypertension is present. Daily subcutaneous injections of 200 micrograms, a low physiological dose, significantly increase the blood pressure of unilaterally nephrectomized saline-treated rats after 2 weeks. This strengthens the hypothesis that 18-hydroxydeoxycorticosterone contributes to the etiology of hypertension, possibly by a mechanism involving stressinduced release of adrenocorticotropic hormone.