Norm-based accounts of social behavior in economics typically reflect tradeoffs between maximization of own consumption utility and conformity to social norms. Theories of norm-following tend to assume that there exists a single, stable, commonly known injunctive social norm for a given choice setting and that each person has a stable propensity to follow social norms. We collect panel data on 1468 participants aged 11–15 years in Belfast, Northern Ireland and Bogotá, Colombia in which we measure norms for the dictator game and norm-following propensity twice at 10 weeks apart. We test these basic assumptions and find that norm-following propensity is stable, on average, but reported norms show evidence of change. We find that individual-level variation in reported norms between people and within people across time has interpretable structure using a series of latent transition analyses (LTA) which extend latent class models to a panel setting. The best fitting model includes five latent classes corresponding to five sets of normative beliefs that can be interpreted in terms of what respondents view as “appropriate” (e.g. equality vs. generosity) and how they view deviations (e.g. deontological vs. consequentialist). We also show that a major predictor of changing latent classes over time comes from dissimilarity to others in one’s network. Our application of LTA demonstrates how researchers can engage with heterogeneity in normative perceptions by identifying latent classes of beliefs and deepening understanding of the extent to which norms are shared, stable, and can be predicted to change. Finally, we contribute to the nascent experimental literature on the economic behavior of children and adolescents.

Peer support interventions for dietary change may offer cost-effective alternatives to interventions led by health professionals. This process evaluation of a trial to encourage the adoption and maintenance of a Mediterranean diet in a Northern European population at high CVD risk (TEAM-MED) aimed to investigate the feasibility of implementing a group-based peer support intervention for dietary change, positive elements of the intervention and aspects that could be improved. Data on training and support for the peer supporters; intervention fidelity and acceptability; acceptability of data collection processes for the trial and reasons for withdrawal from the trial were considered. Data were collected from observations, questionnaires and interviews, with both peer supporters and trial participants. Peer supporters were recruited and trained to result in successful implementation of the intervention; all intended sessions were run, with the majority of elements included. Peer supporters were complimentary of the training, and positive comments from participants centred around the peer supporters, the intervention materials and the supportive nature of the group sessions. Attendance at the group sessions, however, waned over the intervention, with suggested effects on intervention engagement, enthusiasm and group cohesion. Reduced attendance was reportedly a result of meeting (in)frequency and organisational concerns, but increased social activities and group-based activities may also increase engagement, group cohesion and attendance. The peer support intervention was successfully implemented and tested, but improvements can be suggested and may enhance the successful nature of these types of interventions. Some consideration of personal preferences may also improve outcomes.

This study aimed to evaluate the feasibility of a peer support intervention to encourage adoption and maintenance of a Mediterranean diet (MD) in established community groups where existing social support may assist the behaviour change process. Four established community groups with members at increased Cardiovascular Disease (CVD) risk and homogenous in gender were recruited and randomised to receive either a 12-month Peer Support (PS) intervention (PSG) (n 2) or a Minimal Support intervention (educational materials only) (MSG) (n 2). The feasibility of the intervention was assessed using recruitment and retention rates, assessing the variability of outcome measures (primary outcome: adoption of an MD at 6 months (using a Mediterranean Diet Score (MDS)) and process evaluation measures including qualitative interviews. Recruitment rates for community groups (n 4/8), participants (n 31/51) and peer supporters (n 6/14) were 50 %, 61 % and 43 %, respectively. The recruitment strategy faced several challenges with recruitment and retention of participants, leading to a smaller sample than intended. At 12 months, a 65 % and 76·5 % retention rate for PSG and MSG participants was observed, respectively. A > 2-point increase in MDS was observed in both the PSG and the MSG at 6 months, maintained at 12 months. An increase in MD adherence was evident in both groups during follow-up; however, the challenges faced in recruitment and retention suggest a definitive study of the peer support intervention using current methods is not feasible and refinement based on the current feasibility study should be incorporated. Lessons learned during the implementation of this intervention will help inform future interventions in this area.

Adhering to a Mediterranean diet (MD) is associated with reduced CVD risk. This study aimed to explore methods of increasing MD adoption in a non-Mediterranean population at high risk of CVD, including assessing the feasibility of a developed peer support intervention. The Trial to Encourage Adoption and Maintenance of a MEditerranean Diet was a 12-month pilot parallel group RCT involving individuals aged ≥ 40 year, with low MD adherence, who were overweight, and had an estimated CVD risk ≥ 20 % over ten years. It explored three interventions, a peer support group, a dietician-led support group and a minimal support group to encourage dietary behaviour change and monitored variability in Mediterranean Diet Score (MDS) over time and between the intervention groups, alongside measurement of markers of nutritional status and cardiovascular risk. 118 individuals were assessed for eligibility, and 75 (64 %) were eligible. After 12 months, there was a retention rate of 69 % (peer support group 59 %; DSG 88 %; MSG 63 %). For all participants, increases in MDS were observed over 12 months (P < 0·001), both in original MDS data and when imputed data were used. Improvements in BMI, HbA1c levels, systolic and diastolic blood pressure in the population as a whole. This pilot study has demonstrated that a non-Mediterranean adult population at high CVD risk can make dietary behaviour change over a 12-month period towards an MD. The study also highlights the feasibility of a peer support intervention to encourage MD behaviour change amongst this population group and will inform a definitive trial.

Age-related hearing loss (ARHL) is common and a known risk factor for social disengagement in later life. This study explored social functioning following a diagnosis of ARHL. Using a constructivist grounded theory approach we developed an interview schedule to advance a grounded theory from data collected from six older adults who used either hearing aids or cochlear implants. Interview questions concerned social functioning as well as focusing on their perspective of the impact of ARHL on cognitive functioning. We describe a grounded theory conceived as ‘Reconnecting to Others’. This theory posits that participants faced social challenges in relation to their ARHL, and resolved these challenges partly through the use of hearing aids and cochlear implantation. The theory also emphasises the importance of help from other hearing aid users for new users, and corroborates prior findings about strategies older adults with ARHL use to cope with their hearing impairment in various social situations. Once hearing aids and cochlear implants are used and adapted to with the help of peers, participants completed their journey by helping others who had received diagnoses of ARHL. Additionally, participants spoke of the pleasure of hearing again. Interestingly, no participant felt that their ARHL had impacted their cognitive functioning. Our theory provides a basis for explaining existing quantitative findings as well as creating new hypotheses for future testing.

Accurate assessment of dietary intake in older populations is important for determining the role of diet in healthy ageing. The food frequency questionnaire (FFQ) is a commonly used dietary assessment tool, however there is limited evidence regarding its utility for accurately assessing fruit and vegetable (FV) intake in older adults. The objective of this study was to validate FV intakes estimated from the FFQ used in the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) against a food diary (FD).

A dietary validation study was conducted in a sub-sample of 95 participants (45 males, 50 females, aged > 50 years) from NICOLA. Participants were asked to complete a FFQ and 4-day FD (reference method) at two time-points (Month 0 and Month 6). Self-reported FV intakes were compared between methods using Spearman's correlation coefficients, examining the percentage of participants classified into the same or adjacent quartile of FV intake, weighted kappa and Bland-Altman plots.

Median fruit, vegetable and total FV intake were significantly higher in the FFQ than the FD at both Month 0 and Month 6 (all p < 0.001). Significant positive correlations (all p < 0.05) were observed between the FFQ and FD estimates of FV intake at both time-points (Month 0, r = 0.57, 0.50 and 0.49 for fruit, vegetables, total FV, respectively; Month 6 r = 0.56, 0.42 and 0.50, respectively). When FV intakes were classified into fourths (based upon quartiles of total FV portions by FD or FFQ), 80 % and 79 % of participants were classified into the same or adjacent quartile at Month 0 and Month 6, respectively. Weighted kappa indicated a fair-moderate agreement between the two methods for FV intake (weighted kappa = 0.35 and 0.37 at Month 0 and Month 6, respectively). Bland-Altman plots showed that, as FV intake increased, there was a widening in limits of agreements, between the FFQ and FD. There was also a significant positive correlation noted between total FV intakes reported at Month 0 and those reported at Month 6 (r = 0.70, p < 0.001).

Over-reporting of FV intake was evident with the FFQ compared to the FD, however, the results showed good comparability between the methods in being able to rank older adults according to their FV intake. An additional analysis of FV biomarkers obtained from this sample will provide a more objective assessment of FV intake by each method.

A longstanding issue in the field of nutrition is the potential inaccuracy of methods traditionally used for dietary assessment (i.e. food diaries and food frequency questionnaires). It is possible to overcome the limitations and biases of these techniques by combining them with analytical measurements in human biofluids. Metabolomic technologies are gaining popularity as nutritional tools due to their capacity to measure metabolic responses to external stimuli, such as the ingestion of certain foods. This project performed both LC-MS and 1H-NMR metabolomic profiling on serum samples collected as part of the NICOLA study (Northern Irish Cohort for the Longitudinal Study of Aging) in order to discover novel dietary biomarkers. A dietary validation cohort (NIDAS) was incorporated within NICOLA, involving 45 males and 50 females, aged 50 years and over. Participants provided detailed dietary data (4-day food diary) and blood samples at two time-points, six months apart. Serum samples were processed on two analytical platforms. 1H-NMR spectra were acquired using a Bruker 600 MHz Ascent coupled to a TCI cryoprobe and processed using Bayesil (University of Alberta, Canada). A Waters TQ-S coupled with an Acquity I-class UPLC was used in combination with a targeted commercially available kit (AbsoluteIDQ p180 kit, Biocrates). Mass spectra obtained were processed with MetIDQ and verified using MassLynx (v4.1). Data were tested for normality, and metabolite concentrations were correlated with recorded dietary intake of each food type using SPSS. Additional tests (PCA, PLS-DA, ROC Curves) were performed on MetaboAnalyst 4.0 (University of Alberta, Canada). More than 50 statistically significant (P < 0.05) food-metabolite correlations were detected, 15 of which remained significant after eliminating potential confounding from sex, age and BMI. The strongest correlations were between fruit consumption and acetic acid, and between dairy consumption and certain glycerophospholipids (e.g. LysoPC aa C20:3). Stratifying the cohort by gender yielded further correlations, including PC ae C38:2 (dairy; males), PC aa C34:4 (dairy; females), PC aa C36:4 (dairy; females) and trans-4-Hydroxyproline (meat; males). A number of potential blood-based food biomarkers were detected, many of which are gender-specific, and some are corroborated by previously published studies. However, further validation work is required. For example, biological plausibility needs to be established, and the findings need to be reproduced in other cohorts to demonstrate their applicability in larger and more diverse populations. These results contribute greatly to the ongoing efforts to discover and validate reliable nutritional biomarkers as an objective and unbiased measurement of food intake.

Introduction: Postpartum weight management is difficult for many mothers due to the demands of parenthood. Women have highlighted a need for support but experience barriers to engaging with lifestyle interventions hence more adaptable approaches are required. This work examined participants’ engagement with a 12-month, theory-based, automated, text message (SMS) delivered, intervention supporting postpartum weight management.

Methods: SMS content was informed by: 1) the ‘Health Action Process Approach’ (HAPA)1; 2) behaviour change techniques associated with effectiveness in weight management interventions2; 3) women's accounts of postpartum weight-related experiences; and 4) personal and public involvement. A two-arm pilot RCT recruited women within two years postpartum, with a BMI ≥ 25 kg/m2, through community sources and social media. Women were randomised via a secure remote system to receive the intervention or an active control delivering child development messages. Participants received 353 messages during the 12 month intervention. Two-way messages were used to assess engagement: 50 messages prompted women to respond with their weight; 36 interactive messages requested participants’ to respond ‘Yes/No’ to a question which then triggered a feedback message. Participant engagement with two-way messages was calculated as a percentage of replies sent by women and was categorised as ‘high’ or ‘low’ according to the median number of replies sent. Weight was measured at 0, 3, 6, 9 and 12 months.

Results: 51 of 100 women recruited were randomised to receive the intervention. In months 0–6, (47%) and (95%) of participants responded to the weight messages and the ‘Yes/No’ messages respectively. In months 7–12, the responses were (77%) and (86%) respectively. Participants who were high engagers with weight messages had greater mean weight loss compared with low engagers at all time points: at 12 months high engagers (n = 18) lost -2.66 kg and had a reduction in waist circumference at 12 months of -8.9 cm, compared to changes in low engagers (n = 18) of -0.84 kg and -3.6 cm. Likewise, high engagers with ‘Yes/No’ messages had greater mean weight loss compared with low engagers at all time points: at 12 months high engagers (n = 16) lost -2.87 kg and had a reduction in waist circumference of -9.4 cm, compared to changes in low engagers (n = 20) of -0.86 kg and -3.6 cm.

Discussion: The use of two-way text messages was a useful way to encourage engagement with this SMS-delivered intervention. Higher engagement resulted in more weight loss compared to low engagement.

Increased fruit and vegetable (FV) intake is associated with reduced blood pressure (BP). However, it is not clear whether the effect of FV on BP depends on the type of FV consumed. Furthermore, there is limited research regarding the comparative effect of juices or whole FV on BP. Baseline data from a prospective cohort study of 10 660 men aged 50–59 years examined not only the cross-sectional association between total FV intake but also specific types of FV and BP in France and Northern Ireland. BP was measured, and dietary intake assessed using FFQ. After adjusting for confounders, both systolic BP (SBP) and diastolic BP (DBP) were significantly inversely associated with total fruit, vegetable and fruit juice intake; however, when examined according to fruit or vegetable sub-type (citrus fruit, other fruit, fruit juices, cooked vegetables and raw vegetables), only the other fruit and raw vegetable categories were consistently associated with reduced SBP and DBP. In relation to the risk of hypertension based on SBP >140 mmHg, the OR for total fruit, vegetable and fruit juice intake (per fourth) was 0·95 (95 % CI 0·91, 1·00), with the same estimates being 0·98 (95 % CI 0·94, 1·02) for citrus fruit (per fourth), 1·02 (95 % CI 0·98, 1·06) for fruit juice (per fourth), 0·93 (95 % CI 0·89, 0·98) for other fruit (per fourth), 1·05 (95 % CI 0·99, 1·10) for cooked vegetable (per fourth) and 0·86 (95 % CI 0·80, 0·91) for raw vegetable intakes (per fourth). Similar results were obtained for DBP. In conclusion, a high overall intake of fruit, vegetables and fruit juice was inversely associated with SBP, DBP and risk of hypertension, but this differed by FV sub-type, suggesting that the strength of the association between FV sub-types and BP might be related to the type consumed, or to processing or cooking-related factors.

This study uses simulation over real and artificial networks to compare the eventual adoption outcomes of network interventions, operationalized as idealized contagion processes with different sets of seeds. While the performance depends on the details of both the network and behaviour adoption mechanisms, interventions with seeds that are central to the network are more effective than random selection in the majority of simulations, with faster or more complete adoption throughout the network. These results provide additional theoretical justification for utilizing relevant network information in the design of public health behavior interventions.

Bovine β-lactoglobulin (BLG) in vivo has been found complexed with fatty acids, especially palmitic and oleic acid. To elucidate the still unknown structure-function relationship in this protein, the interactions between 13C enriched palmitic acid (PA) and BLG were investigated by means of one-, two-, and three-dimensional NMR spectroscopy in the pH range 8.4–2.1. The NMR spectra revealed that at neutral pH the ligand is bound within the central cavity of BLG, with the methyl end deeply buried within the protein. The analysis of 13C spectra of the holo protein revealed the presence of conformational variability of bound PA carboxyl end in the pH range 8.4–5.9, related to the Tanford transition. The release of PA starts at pH lower than 6.0, and it is nearly complete at acidic pH. This finding is relevant in relation to the widely reported hypothesis that this protein can act as a transporter through the acidic gastric tract. Ligand binding and release is shown to be completely reversible over the entire pH range examined, differently from other fatty acid binding proteins whose behavior is analyzed throughout the paper. The mode of interaction of BLG is compatible with the proposed function of facilitating the digestion of milk fat during the neonatal period of calves.