House dust microbiota and atopic dermatitis; effect of urbanization.

BACKGROUND: Previous studies have shown that a child's risk of developing atopic disease is impacted by both genetic and environmental factors. Because small children spend the majority of their time in their homes, exposure to microbial factors in their home environment may be protective or risk factors for development of atopic diseases, such as atopic dermatitis. METHODS: Dust samples from the homes of 86 Black South African children 12 to 36 months old were collected for analysis of the bacterial microbiome. This case-control study design included children with and without atopic dermatitis from rural and urban environments. RESULTS: Significant differences in bacterial composition and diversity were found when comparing children with and without atopic dermatitis. Furthermore, house dust microbiota was significantly different in rural and urban areas. Differences were best accounted for by higher relative abundance of Ruminococcaceae, Lachnospiraceae, and Bacteroidaceae families in rural compared with urban houses. Levels of Ruminococcaceae were also found to be significantly depleted in the house dust of rural children with atopic dermatitis as compared to control children. CONCLUSIONS: House dust composition may be an important risk factor for the development of atopic disease, and this association may be driven in part by the gut microbiome. Low levels of the Ruminococcaceae family from Clostridia class in particular may explain the association between urban living and atopy. However, further research is needed to elucidate these links.

Environmental factors associated with allergy in urban and rural children from the South African Food Allergy (SAFFA) cohort.

BACKGROUND: The prevalence of allergic diseases differs in urban and rural populations. OBJECTIVE: We sought to assess associations between environmental and dietary factors with allergic diseases in urban and rural South African children. METHODS: Toddlers aged 12 to 36 months were assessed for food allergen and aeroallergen sensitization, atopic dermatitis, allergic rhinitis, asthma, and challenge-proved food allergy. Information was collected on family history of allergic diseases, household size, socioeconomic status, delivery mode, antibiotic and probiotic use, exposure to fermented and unpasteurized milk, antihelminth treatment, sunlight exposure, pet and farm animal exposure, cigarette smoke, and household cooking and heating fuels. Antenatal exposures to pets, livestock, and cigarette smoke were assessed. A subsection completed questions on consumption of fruits and vegetables, fast foods, soft drinks/fruit juices, and fried/microwaved meat. RESULTS: Risk and protective factors differed between urban and rural settings. Exposure to farm animals in infants and their mothers during pregnancy was protective against allergic outcomes in the rural population. Consumption of unpasteurized milk is uncommon in this group of rural children and is unlikely to be an important factor in rural protection. In urban children birth by cesarean section is associated with food allergy, and consumption of fermented milk products is associated with reduced asthma and atopic dermatitis. In both cohorts antenatal maternal smoking and environmental smoking exposure were predominantly associated with asthma, and consumption of fast foods and fried meats were associated with allergy. CONCLUSION: In this rural environment exposure to livestock is the strongest protective factor. In urban communities, where animal contact is rare, risk factors include cesarian section, and protective factors include consumption of fermented milk products. Modifiable risk factors urgently require interventions to prevent increasing allergy rates in countries undergoing rapid urbanization.

Rural and urban food allergy prevalence from the South African Food Allergy (SAFFA) study.

BACKGROUND: Food sensitization and challenge-proved food allergy (FA) have not been compared in urban and rural settings. OBJECTIVE: We sought to determine and compare the prevalence of food sensitization and challenge-proved IgE-mediated FA in urban and rural South African toddlers aged 12 to 36 months. METHODS: This cross-sectional study of unselected children included 1185 participants in urban Cape Town and 398 in the rural Eastern Cape. All participants completed a questionnaire and underwent skin prick tests (SPTs) to egg, peanut, cow's milk, fish, soya, wheat, and hazelnut. Participants with SPT responses of 1 mm or greater to 1 or more foods and not tolerant on history underwent an open oral food challenge. RESULT: The prevalence of FA was 2.5% (95% CI, 1.6% to 3.3%) in urban children, most commonly to raw egg white (1.9%), followed by cooked egg (0.8%), peanut (0.8%), cow's milk (0.1%), and fish (0.1%). Urban sensitization (SPT response ≥1 mm) to any food was 11.4% (95% CI, 9.6% to 13.3%) and 9.0% (95% CI, 7.5% to 10.8%) at an SPT response of 3 mm or greater. Sensitization in rural cohorts was significantly lower than in the urban cohort (1-mm SPT response, 4.5% [95% CI, 2.5% to 6.6%]; 3-mm SPT response, 2.8% [95% CI, 1.4% to 4.9%]; P < .01). In the rural black African cohort 0.5% (95% CI, 0.1% to 1.8%) of children had food allergy, all to egg. This is significantly lower than the prevalence of the urban cohort overall (2.5%) and urban black African participants (2.9%; 95% CI, 1.5% to 4.3%; P = .006). CONCLUSION: FA prevalence in Cape Town is comparable with rates in industrialized middle-income countries and is significantly greater than in rural areas. Further analysis will describe and compare environmental exposures and other risk factors in this cohort.

Nutrition and allergic diseases in urban and rural communities from the South African Food Allergy cohort.

This study describes and compares allergic diseases and sensitization in urban and rural children in the SAFFA study cohort as well as infant feeding patterns and nutritional status. We assessed the relationship between nutritional status, breastfeeding, complementary feeding patterns, and atopic diseases including aeroallergen and food allergen sensitization, self-reported atopic dermatitis, allergic rhinitis, asthma, and challenge-proven food allergy (FA). METHODOLOGY: A total of 1185 urban and 398 rural toddlers aged 12-36 months were screened for food sensitization (FS) and FA using skin prick testing and oral food challenges. Of these, 535 and 347, respectively, were additionally screened for aeroallergen sensitization. Information was collected on infant feeding practices, and anthropometric measurements and clinical signs for atopy were documented. RESULTS: Markedly higher rates of allergy (asthma 9.0% vs 1.0%, eczema 25.6% vs 2.0%, rhinitis 25.3% vs 3.3%, and FA 2.5% vs 0.5%) exist in urban vs rural children. 13.1% unselected urban South African children were sensitized to aeroallergens compared to 3.8% of their rural counterparts and 9.0% to any food compared to 0.5%. Exclusive breastfeeding duration was longer, and there was a later introduction of allergenic foods in rural communities. Obesity rates were similar between the two groups, but rural children were more likely to be stunted. Being overweight was associated with asthma in urban but not rural settings. In the urban cohort, children with FS and allergy were thinner than their peers. CONCLUSION: Allergy and sensitization rates are significantly higher in unselected urban South African toddlers than their rural counterparts. Risk and protective factors for allergy and atopy may differ between urban and rural settings.

The South African Food Sensitisation and Food Allergy population-based study of IgE-mediated food allergy: validity, safety, and acceptability.

BACKGROUND: Few studies exist on food sensitization and challenge-proven food allergy in low- and middle-income countries. OBJECTIVE: To describe the study design and methodology to recruit infants from an African population for skin prick testing and oral food challenges and the use of preliminary data to investigate the extent to which the study sample is representative of the target population. METHODS: Children 12 to 36 months old were recruited from childcare education facilities in Cape Town. Children underwent skin prick testing to foods. Those with a reactive wheal of at least 1 mm larger than the negative control and not clearly tolerant according to history to a full age-appropriate portion to at least 1 food underwent oral food challenges. Parents who chose not to participate completed a nonparticipant questionnaire. Interim analysis of at least 500 respondents was performed. Demographic features of participating children were compared with those of nonparticipants and the population demographics of the most recent Cape Town census data. RESULTS: The response rate was 60.1%, with high participation and completion rates of 96.5% and 97.5%, respectively. Demographics of the completed participant sample were similar to those of the Cape Town census. Use of a nonrespondent questionnaire indicated no selection bias in favor of increased participation of participants with allergy. No ethnic differences in sensitization or food allergy were evident. CONCLUSION: The study was safe and feasible and the recruitment was effective and representative of the target population. Future studies will aim to increase the precision of the prevalence of food sensitization and allergy, describe environmental risk factors, and include a rural black African cohort.

Every "Body" Gets a Say: An Augmented Optimization Metric to Preserve Body Pose during Avatar Adaptation in Mixed/Augmented Reality.

User-Avatar interaction within augmented reality applications is rapidly increasing in frequency. Applications routinely place users in rooms with other, remote users embodied by photorealistic avatars, or require users to work with an avatar of a remote user to complete a task. During these types of interactions, it is often required to modify or redirect the posture of an avatar to achieve goals such as contact with or pointing at an object or maintaining eye gaze with the local user. A key limitation of modern redirection techniques is successfully preserving body posture, a critical component of nonverbal communication. This paper presents a new pose-preserving objective function to be used in the multi-objective optimization of an avatar's kinematic configuration. This objective function not only mimics the correct placement of body joints, but also preserves their orientation in space. We have tested this approach against several commonly used and current state-of-the-art redirection techniques and have found that our new approach achieves a significant reduction in targeted redirection error while simultaneously reducing body posture error. Additionally, human subject testing has shown that our new technique provides both a significantly more natural looking redirection and a significantly more realistic and believable overall body posture.

Instilling the perception of weight in augmented reality using minimal haptic feedback.

Humans perceive gravitational forces on their surroundings through a mix of visual and sensorimotor cues. The accurate presentation of such cues is a difficult task in Mixed/Augmented Reality (MR/AR), technological paradigms that blend physical and virtual elements to enhance the way we interact with our environment. Realistically perceiving the weight of virtual elements within a MR/AR scenario aids in the embodiment of those elements within the user's reality, further blurring the lines between what is real and virtual. Unfortunately, current force feedback devices are not designed for or are entirely compatible with MR/AR experiences. To address this need, we explore minimal haptic feedback for weight perception in MR/AR, aiming to simplify the rendering of gravitational cues that are crucial to an immersive experience. Our benchtop device, focused on wrist feedback, showed improved user experience even within an implicit weight feedback task, i.e., a task where weight perception was not required for task completion. However, challenges arose in mixed real-virtual environments, a cornerstone of MR/AR interaction, where weight discrimination was observed to be less accurate. To address this, we developed a compensation scheme for virtual weights, leading to performance on par with a purely virtual environment. Our work demonstrates the viability of minimal haptic feedback in MR/AR applications and highlights the importance of integrating weight perception for increased realism. Our work also fills a research gap in MR/AR development, providing insights for designing future MR/AR systems that integrate with human sensory mechanisms to create virtual interactions that more closely mirror the physical world.

An Iterative Participatory Design Approach to Develop Collaborative Augmented Reality Activities for Older Adults in Long-Term Care Facilities.

Over four million older adults living in long-term care (LTC) communities experience loneliness, adversely impacting their health. Increased contact with friends and family is an evidence-based intervention to reduce loneliness, but in-person visits are not always possible. Augmented Reality (AR)-based telepresence activities can offer viable alternatives with increased immersion and presence compared to video calls. However, its feasibility as an interaction technology for older adults is not known. In this paper, we detail the design of two dyadic collaborative AR activities that accommodate diminished physical and cognitive abilities of older adults. The findings include a general design framework based on an iterative participatory design focusing on preferred activities, modes of interaction, and overall AR experience of eight older adults, two family members, and five LTC staff. Results demonstrate the potential of collaborative AR as an effective means of interaction for older adults with their family, if designed to cater to their needs.