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Background: There is a limited understanding of the dynamic influences that shape infant and young child feeding (IYCF) decisions over time. We conducted an innovative qualitative study to reconstruct IYCF trajectories across early life course phases, in the context of the socioecological model (SEM) and the commercial determinants of IYCF. Methods: Women of different socioeconomic status were interviewed in two large metropolitan areas in Mexico. Our specific goal was to allow us to better understand if and how the commercial milk formula (CMF) marketing influenced breastfeeding decisions in a complex dynamic way involving the individual, relational, community and societal levels. Results: Hospitals, health professionals, and interactions with social media were key category entry points throughout the prenatal, perinatal, early infancy period and beyond. The CMF industry interfered by engaging a wide array of actors across the different layers of the SEM, most prominently the health care system and the workplace. Through its marketing strategies the CMF operates subconsciously and its messages are most effective when health institutions, health care providers, workplace spaces and social norms are weak in their support for breastfeeding. Conclusions: The cases in our study highlight how, together with a weak breastfeeding counseling system, and health professionals who lack training in breastfeeding and normal infant behavior, lead to the opportunity for CMF marketing to shape infant feeding, and ultimately to the decision to feed formulas that some mothers were not planning to use and cannot afford. [ABSTRACT FROM AUTHOR]

Background: Mothers play a crucial role in influencing their daughters' HPV vaccination decisions. Addressing barriers to receiving HPV vaccination among mothers of girls may achieve two goals in one strike: increasing vaccination coverage among both mothers and their daughters. This study aims to examine the HPV vaccination uptake and its determinants among mothers of girls in China at both the individual and interpersonal levels. Methods: From July to October 2023, a cross-sectional online study was conducted to investigate HPV vaccine refusal for daughters aged 9–17 years among 11,678 mothers in Shenzhen, China. A randomized selection method was employed, targeting 11 primary schools and 13 secondary schools in Shenzhen. The research team invited mothers of girls to participate in an anonymous online survey. Multilevel logistic regression models (level 1: schools; level 2: individual participants) were employed to analyze the data. Results: Among 11,678 mothers, 41.1% self-reported receiving at least one dose of HPV vaccination. Through multilevel logistic regression analysis, eight items measuring illness representations of HPV, which refers to how people think about HPV, were associated with higher HPV vaccination uptake (AOR: 1.02–1.14). These items included identity (identifying symptoms of HPV), timeline (whether HPV is acute/chronic), negative consequences, personal and treatment control (whether HPV is under volitional control), concern, negative emotions, and coherence (overall understanding of HPV). In addition, participants refusing HPV vaccines for the index daughters (AOR: 0.82, 95%CI: 0.76, 0.89) had lower vaccine uptake. Perceived more difficulties in accessing the 9-valent vaccines (AOR: 1.06, 95%CI: 1.04, 1.08) and more satisfaction with vaccine-related promotional materials (AOR: 1.50, 95%CI: 1.46, 1.54) at the individual level were associated with higher vaccine uptake. At the interpersonal factors, higher frequency of exposure to testimonials given by others about HPV vaccination on social media (AOR: 1.19, 95%CI: 1.14, 1.25) and thoughtful consideration of the veracity of the information (AOR: 1.11, 95%CI: 1.07, 1.16) were correlated with higher HPV vaccination uptake. Conclusions: These findings offer essential implications for modifying HPV disease perceptions, addressing difficulties in accessing the 9-valent HPV vaccines, and enhancing health communication needs to improve HPV vaccine uptake among mothers of girls. [ABSTRACT FROM AUTHOR]

Background: Advance care planning (ACP) can contribute to individuals making decisions about their healthcare preferences in advance of serious illness. Up to now, the acceptance level and associated factors of ACP among the public in China remain unclear. This study aims to investigate the acceptance level of ACP in China and identify factors associated with it based on the socioecological model. Methods: A total of 19,738 participants were included in this survey. We employed a random forest regression analysis to select factors derived from the socioecological model. Multivariate generalized linear model analysis was then conducted to explore the factors that were associated with the acceptance level of ACP. Results: On a scale ranging from 0 to 100, the median score for acceptance level of ACP was 64.00 (IQR: 48.00–83.00) points. The results of the multivariate generalized linear model analysis revealed that participants who scored higher on measures of openness and neuroticism personality traits, as well as those who had greater perceptions of social support, higher levels of health literacy, better neighborly relationships, family health, and family social status, were more likely to accept ACP. Conversely, participants who reported higher levels of subjective well-being and greater family communication levels demonstrated a lower likelihood of accepting ACP. Conclusions: This study identified multiple factors associated with the acceptance level of ACP. The findings offer valuable insights that can inform the design and implementation of targeted interventions aimed at facilitating a good death and may have significant implications for the formulation of end-of-life care policies and practices in other countries facing similar challenges. [ABSTRACT FROM AUTHOR]

Background: Mounting evidence is revealing disparities in cognitive function and heightened dementia risk among refugees, yet research in this area remains scant. Despite bearing most of the world's refugee burden, limited-resource countries like Jordan are facing challenges when dealing with refugee health. There is a lack of research on the attitudes toward dementia and the cognitive healthcare gaps among refugees in Jordan. Methods: 32 older (≥ 55 years) Syrian refugees resettled in Jordan were recruited through a local community-based organization and interviewed in four focus groups (2 female and 2 male groups). Interviews were transcribed and translated, then coded using inductive thematic analysis. Results: Mean age of the sample was 60.1 years and 53.1% were female. Only 34.4% rated their memory as good or excellent. Themes were organized using the socioecological model: 1) At the individual level, participants believed high levels of stress, including low socioeconomic status, poor health, and traumatic history from their refugee experience increased their dementia risk. 2) Interpersonally, there is a fear of dementia due to the possible impact and burden on loved ones, particularly with the stigma surrounding dementia. 3) At the community level, participants noted that resettlement in Jordan – with a shared language, religion, and culture – offered protective effects due to facilitated access to social connection, information, and mental health self-care. 4) At the institution and policy level, participants believed older refugees faced restrictive policies for economic aid, healthcare, and employment, presenting a significant barrier to healthy aging. Conclusions: Findings from this study are the first to examine the attitudes of Syrian refugees in Jordan toward dementia and cognitive aging. These results could provide essential data inclusive of refugees as Jordan develops its National Dementia Plan. Investing in dementia awareness interventions and age-friendly neighborhoods may benefit aging refugees in limited-resources settings. [ABSTRACT FROM AUTHOR]

Background: The eating behaviors of older adults are associated with multiple factors. To promote older adults’ healthy diets, it is imperative to comprehensively study the factors associated with the eating behaviors of the aging population group. This study aimed to probe the associated factors of older adults’ eating behaviors from a socioecological model (SEM) perspective. Methods: In 2021, a cross-sectional survey was performed to recruit participants in China. The survey data were analyzed using a multivariate generalized linear model to identify the factors associated with eating behaviors in older adults. Standardized regression coefficients (β) and 95% confidence intervals (CIs) were estimated using a multivariate generalized linear model. Results: The survey contained 1147 valid older adult participants. Multivariate generalized linear model results showed that older adults with older age [aged 71–80 (β = -0.61), ≥ 81 (β = -1.12)], conscientiousness personality trait (β = -0.27), and higher family health levels (β = -0.23) were inclined to have better eating behaviors. The older adults with higher education levels [junior high school and high school (β = 1.03), junior college and above (β = 1.71)], higher general self-efficacy (β = 0.09), more severe depression symptoms (β = 0.24), and employment (β = 0.82) tended to have poorer eating behaviors. Conclusions: This study identified factors that are specifically associated with older adults’ eating behaviors from an SEM perspective. The comprehensive multiple-angle perspective consideration may be a valuable idea for studying healthy eating behaviors in older adults. [ABSTRACT FROM AUTHOR]

Background: Handwashing with soap is a cost-effective, efficient health behavior to prevent various diseases. Despite its immense health benefits, the lowest prevalence of handwashing is found in low-income countries. Here, its practice is not only determined by individual behavior, but also heavily shaped by deprivations in the social and structural ecology. Moreover, handwashing barriers are not equally experienced as overlapping social identities (e.g., age and gender) intersect and create inequities between members of different social groups. To embrace the complexities of handwashing beyond individual-level behavior and singular social identities, a combined socioecological and intersectional perspective is employed. This multi-level approach with regards to intersecting privileges and disadvantages serves as a basis to promote this highly important health behavior. Methods: This study used a qualitative, theory-based approach and combined data from two samples: experts in health promotion (n = 22) and local citizens stratified by gender and rural/urban location (n = 56). Data was collected in face-to-face interviews in Sierra Leone between November 2018 and January 2019 and analyzed using thematic analysis and typology of the qualitative data. Results: The conceptualization of multi-level determinants of handwashing within a socioecological model showed the high relevance of inhibiting social and structural factors for handwashing practice. By establishing seven distinguishing social identity dimensions, data demonstrates that individuals within the same social setting yet with distinct social identities experience strikingly differing degrees of power and privileges to enact handwashing. While a local leader is influential and may also change structural-level determinants, a young, rural wife experiences multiple social and structural constraints to perform handwashing with soap, even if she has high handwashing intentions. Conclusion: This study provides a holistic analytical framework for the identification of determinants on multiple levels and accumulating intersections of socially produced inequalities for handwashing and is applicable to other health topics. As the exploration of handwashing was approached from a solution-focused instead of a problem-focused perspective, the analysis can guide multi-level intervention approaches (e.g., using low-cost, participatory activities at the community level to make use of the available social capital). [ABSTRACT FROM AUTHOR]

Although public engagement in research is increasingly popular, the involvement of citizens living in vulnerable circumstances is rarely realized. This narrative review aims to describe and critically analyse concerns and corresponding strategies, tools, and methods that could support the inclusion of these citizens in health research. The 40 studies that are included were thematically analysed using the socioecological model. Concerns originate most often on the intrapersonal level of the socioecological model, but concerns were also identified at institutional, community, and policy levels. It is thought-provoking that there is a lack of attention for the research and policy structure in which engagement practices are designed, implemented and evaluated. More research is needed to explore how these cultures could be changed in a way that promotes rather than restrains the engagement of citizens living in vulnerable circumstances in research and policymaking. Plain English summary: Unfortunately, citizens living in vulnerable circumstances are seldom engaged in research or policymaking. Think of, citizens living in poverty, those with an ethnic minority background or citizens with mental health issues are often excluded. Their involvement is, however, crucial to prevent growing (health) inequalities. To support the engagement of people living in vulnerable circumstances we conducted a literature review. We looked for strategies, tools, and methods that could support the inclusion of these citizens in research or policymaking. In total, 40 studies were identified and analysed. The main finding is that strategies tools, and methods are always context depended. Researchers should always ask: What works for whom in which context? We, therefore, stress the importance of close collaboration with experienced owners and community based organisations from the start. Also, more attention should be paid to how engagement practices are designed, implemented and evaluated. Think of, strict deadlines which limit the time to build trust. Or low budgets that limit the options to create the right preconditions, think of recruitment and data collection in multiple languages. To make sure that not only the 'usual suspects' but also citizens living in vulnerable circumstance will be engaged attention is needed from advocacy groups, research funders and researchers. All these actors need to reflect more often on the question what they can do to change the current research and policymaking culture in such a way that it will support the engagement of citizens living in vulnerable circumstances. [ABSTRACT FROM AUTHOR]

Background: Nigeria is one of the ten countries globally that account for 62% of under- and unvaccinated children worldwide. Despite several governmental and non-governmental agencies' interventions, Nigeria has yet to achieve significant gains in childhood immunization coverage. This study identifies intrapersonal, interpersonal, organizational, community, and policy-level factors that influence childhood immunization uptake from various stakeholders' perspectives using the Socioecological Model (SEM).Methods: Using the Socioecological Model as a guiding framework, we conducted ten focus group sessions with mothers/caregivers and community leaders residing in Lagos state and nine semi-structured interviews with healthcare workers who provide routine immunization services in Lagos state primary healthcare facilities. We performed a qualitative analysis of focus groups and semi-structured interviews using deductive coding methods.Results: The study sample included 44 mothers/caregivers and 24 community leaders residing in Lagos State, Nigeria, and 19 healthcare workers (routine immunization focal persons) working in the primary healthcare setting in Lagos state. Study participants discussed factors at each level of the SEM that influence childhood immunization uptake, including intrapersonal (caregivers' immunization knowledge, caregivers' welfare and love of child/ren), interpersonal (role of individual relationships and social networks), organizational (geographical and financial access to health facilities, health facilities attributes, staff coverage, and healthcare worker attributes), community (community outreaches and community resources), and policy-level (free immunization services and provision of child immunization cards). Several factors were intertwined, such as healthcare workers' education of caregivers on immunization and caregivers' knowledge of vaccination.Conclusions: The reciprocity of the findings across the Socioecological Model levels emphasizes the importance of developing multi-pronged interventions that operate at multiple levels of the SEM. Our results can inform the design of culturally appropriate and effective interventions to address Nigeria's suboptimal immunization coverage. [ABSTRACT FROM AUTHOR]

Background: In the U.S., strong ethnic/racial, socioeconomic, demographic, and geographic breastfeeding (BF) inequities persist, and African American and Hispanic women are less likely to meet their breastfeeding goals compared to White women. This systematic review (SR) was designed to answer the question: What is the impact of breastfeeding interventions targeting ethnic/racial minority women in the U.S. on improving BF initiation, duration and exclusivity rates? Methods: The SR was conducted following the Institute of Medicine Guidelines and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. The study protocol was developed and registered a priori in PROSPERO (ID#CRD42020177764). The electronical databases searched was MEDLINE All (Ovid). Search strategies were led by the team's expert public health librarian using both controlled vocabulary and free text queries and were tested against a validated set of relevant papers included in existing reviews. The GRADE methodology was used to assess the quality of the studies. Results: We included 60 studies that had randomized (n = 25), observational (n = 24), quasi-experimental (n = 9), or cross-sectional (n = 2) designs. The studies focused on populations that were multi-ethnic/racial (n = 22), only Hispanic (n = 24), only Black (n = 13), and only American Indian (n = 1). The study interventions were classified following the socioecological model: macrosystem/policy level (n = 6); community level (n=51), which included healthcare organizations (n = 34), The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) (n = 9), and community organizations/public health institutions (n = 8); and interpersonal level (n = 3). Conclusions: Policy and community level interventions delivered through WIC, healthcare facilities, and community agencies) are likely to improve BF outcomes among women of color. The combination of interventions at different levels of the socioecological model has not been studied among minority women in the U.S. Implementation science research is needed to learn how best to scale up and sustain effective BF interventions, taking into account the needs and wants of minority women. Thus, it is strongly recommended to conduct large scale implementation research studies addressesing how to strengthen the different health and social environments surrounding women of color in the U.S. to improving their BF outcomes. [ABSTRACT FROM AUTHOR]

Language focused on individual dietary behaviors, or alternatively, lifestyle choices or decisions, suggests that what people eat and drink is primarily a choice that comes down to free will. Referring to and intervening upon food consumption as though it were a freely chosen behavior has an inherently logical appeal due to its simplicity and easily defined targets of intervention. However, despite decades of behavioral interventions, population-level patterns of food consumption remain suboptimal. This debate paper interrogates the manner in which language frames how problems related to poor diet quality are understood and addressed within society. We argue that referring to food consumption as a behavior conveys the idea that it is primarily a freely chosen act that can be ameliorated through imploring and educating individuals to make better selections. Leveraging practice theory, we subsequently propose that using the alternative language of eating practices and patterns better conveys the socially situated nature of food consumption. This language may therefore point to novel avenues for intervention beyond educating and motivating individuals to eat more healthfully, to instead focus on creating supportive contexts that enable sustained positive dietary change. Clearly, shifting discourse will not on its own transform the science and practice of nutrition. Nevertheless, the seeds of change may lie in aligning our terminology, and thus, our framing, with desired solutions. [ABSTRACT FROM AUTHOR]

Background: Prechoolers' significant portions of sedentary time (ST) is a public-health concern due to its high prevalence and negative health consequences. However, few studies have explored correlates of preschoolers' ST covering individual-, home- and preschool- factors within one study. The aim of this study was to identify the associations between multiple individual-, home- and preschool-level factors and preschoolers' ST. In addition, it was studied how much individual-, home- and preschool-level factors explained the variance in children's ST.Methods: A total of 864 children aged three to six, their parents and 66 preschools participated in the cross-sectional DAGIS study, which occurred between 2015 and 2016. The children wore an accelerometer for 1 week. Guardians, principals and early educators completed questionnaires covering the potential correlates of children's ST, for example, temperament, practices, self-efficacy and regulations. Multilevel regression analyses were conducted in multiple steps; calculation of marginal and conditional R2 values occurred in the final phase.Results: Of the 29 studied correlates, the following factors remained significant in the final models. Being a boy (p < 0.001) and having high levels of surgency temperament (p < 0.001) were associated with lower ST. Regarding the home setting, frequent co-visits in physical activity (PA) places (p = 0.014) were associated with lower ST. Higher parental perceived barriers related to children's outside PA (p = 0.032) was associated with higher ST. None of the preschool setting factors remained significant in the final model. Approximately 11% of the variance in children's ST was attributed to factors related to the individual level whereas 5% was attributed to home-level factors; and 2% to preschool-level factors.Conclusions: This study identified a set of correlates of preschool children's ST. Interventions aimed at reducing children's ST should develop strategies targeting established correlates of preschoolers' ST covering individual-, home- and preschool-level factors. The preschool-level factors included in this study explained little the variance in children's ST. However, the included measures may not have captured the essential preschool-level factors that specifically influence children's ST. Therefore, more studies are needed regarding potential preschool-level factors. [ABSTRACT FROM AUTHOR]

Background: We sought to understand the multilevel syndemic factors that are concurrently contributing to the HIV epidemic among women living in the US. We specifically examined community, network, dyadic, and individual factors to explain HIV vulnerability within a socioecological framework.Methods: We gathered qualitative data (120 interviews and 31 focus groups) from a subset of women ages 18-44 years (N = 2,099) enrolled in the HPTN 064 HIV seroincidence estimation study across 10 US communities. We analyzed data from 4 diverse locations: Atlanta, New York City (the Bronx), Raleigh, and Washington, DC. Data were thematically coded using grounded theory methodology. Intercoder reliability was assessed to evaluate consistency of team-based coding practices.Results: The following themes were identified at 4 levels including 1) exosystem (community): poverty prevalence, discrimination, gender imbalances, community violence, and housing challenges; 2) mesosystem (network): organizational social support and sexual concurrency; 3) microsystem (dyadic): sex exchange, interpersonal social support, intimate partner violence; and 4) individual: HIV/STI awareness, risk taking, and substance use. A strong theme emerged with over 80 % of responses linked to the fundamental role of financial insecurity underlying risk-taking behavioral pathways.Conclusions: Multilevel syndemic factors contribute to women's vulnerability to HIV in the US. Financial insecurity is a predominant theme, suggesting the need for tailored programming for women to reduce HIV risk.Trial Registration: Clinicaltrials.gov, NCT00995176. [ABSTRACT FROM AUTHOR]

Background: The current political agenda aims to promote active environments and physical activity while commuting to work, but research on it has provided mixed results. This study examines whether the proximity of green space and people's residence in different travel-related urban zones contributes to commuting physical activity.Methods: Population-based cross-sectional health examination survey, Health 2011 study, and geographical information system (GIS) data were utilized. The GIS data on green space and travel-related urban zones were linked to the individuals of the Health 2011 study, based on their home geocoordinates. Commuting physical activity was self-reported. Logistic regression models were applied, and age, gender, education, leisure-time and occupational physical activity were adjusted. Analyses were limited to those of working age, living in the core-urban areas of Finland and having completed information on commuting physical activity (n = 2 098).Results: Home location in a pedestrian zone of a main centre (odds ratio = 1.63; 95 % confidence interval = 1.06-2.51) or a pedestrian zone of a sub-centre (2.03; 1.09-3.80) and higher proportion of cycling and pedestrian networks (3.28; 1.71-6.31) contributed to higher levels of commuting physical activity. The contribution remained after adjusting for all the environmental attributes and individuals. Based on interaction analyses, women living in a public transport zone were almost two times more likely to be physically active while commuting compared to men. A high proportion of recreational green space contributed negatively to the levels of commuting physical activity (0.73; 0.57-0.94) after adjusting for several background factors. Based on interaction analyses, individuals aged from 44 to 54 years and living in sub-centres, men living in pedestrian zones of sub-centres, and those individuals who are physically inactive during leisure-time were less likely to be physically active while commuting.Conclusions: Good pedestrian and cycling infrastructure may play an important role in promoting commuting physical activity among the employed population, regardless of educational background, leisure-time and occupational physical activity. Close proximity to green space and a high proportion of green space near the home may not be sufficient to initiate commuting physical activity in Finland, where homes surrounded by green areas are often situated in car-oriented zones far from work places. [ABSTRACT FROM AUTHOR]

Background: Determinants of waterpipe use in adolescents are believed to differ from those for other tobacco products, but there is a lack of studies of possible social, cultural, or psychological aspects of waterpipe use in this population. This study applied a socioecological model to explore waterpipe use, and its relationship to other tobacco use in Swedish adolescents. Methods: A total of 106 adolescents who attended an urban high-school in northern Sweden responded to an anonymous questionnaire. Prevalence rates for waterpipe use were examined in relation to socio-demographics, peer pressure, sensation seeking behavior, harm perception, environmental factors, and depression. Results: Thirty-three percent reported ever having smoked waterpipe (ever use), with 30 % having done so during the last 30 days (current use). Among waterpipe ever users, 60 % had ever smoked cigarettes in comparison to 32 % of non-waterpipe smokers (95 % confidence interval 1.4-7.9). The odds of having ever smoked waterpipe were three times higher among male high school seniors as well as students with lower grades. Waterpipe ever users had three times higher odds of having higher levels of sensation-seeking (95 % confidence interval 1.2-9.5) and scored high on the depression scales (95 % confidence interval 1.6-6.8) than non-users. The odds of waterpipe ever use were four times higher for those who perceived waterpipe products to have pleasant smell compared to cigarettes (95 % confidence interval 1.7-9.8). Waterpipe ever users were twice as likely to have seen waterpipe use on television compared to non-users (95 % confidence interval 1.1-5.7). The odds of having friends who smoked regularly was eight times higher for waterpipe ever users than non-users (95 % confidence interval 2.1-31.2). Conclusion: The current study reports a high use of waterpipe in a select group of students in northern Sweden. The study adds the importance of looking at socioecological determinants of use, including peer pressure and exposure to media marketing, as well as mental health among users. [ABSTRACT FROM AUTHOR]

Background: Effective interventions that target socioeconomic status (SES) differences to avoid the potential widening of inequalities in health are needed. Children at preschool age is a valuable intervention target since sedentary behaviors, physical activity (PA), dietary behaviors, and sleep habits, jointly called the energy balance-related behaviors (EBRBs), are established in early childhood and tend to persist later in life. The interventions are most effective, when they focus on evidence-based factors. One potential factor associated with EBRBs and SES is children's stress regulation, which receives special attention in this study. Based on the socioecological approach, the combinations of multiple levels (e.g. individual, environmental, societal) of analysis and diverse methodologies (e.g. surveys, observations, biological measurements) are used to assess the healthfulness of environments (e.g. social, physical, learning, policy) in preschool and family settings. The intervention aimed to diminish SES differences in EBRBs is then conducted in the preschool setting. Methods/design: The DAGIS study is divided into two phases. The first phase comprises focus group interviews and a cross-sectional survey. Parents and preschool personnel in low SES neighborhoods participated in interviews about children's sedentary behaviors, dietary behaviors, and PA in 2014. In the cross-sectional survey beginning in autumn 2015, preschools will be recruited from a random sample of preschools in 3-5 municipalities in Southern Finland. A total of 800 children will wear an accelerometer for seven days. Children's hair and saliva samples will be taken. Parents and preschool personnel will complete questionnaires on EBRBs, social and physical environments and SES factors. The quality of preschool environment is also observed. In the second phase, an intervention targeting to narrowing SES differences in EBRBs is conducted. The effects of the intervention will be evaluated in randomised controlled trial. The implementation of the intervention will also be evaluated. Conclusion: If effective, this unique preschool-based study will be able to narrow the SES differences in preschool children's EBRBs. This study is anticipated to identify the most important modifiable factors in preschool and family environmental settings associated with children's EBRBs, especially in children from low SES backgrounds. [ABSTRACT FROM AUTHOR]

Introduction: Species of the order Primates are highly gregarious with most species living in permanent heterosexual social groups. According to theory in socioecology maximum social group size is limited by rates of intra-group feeding competition and associated increases in travel costs. Unlike other hylobatids, which are predominantly pair living, cao vit gibbons (Nomascus nasutus), and two other species of crested gibbon (Nomascus spp.) living in northern seasonal forest, regularly exhibit larger bi-female groups. To better understand the ability of northern gibbons to live in stable bi-female groups, we examined food distribution, feeding competition and reproductive success over a period of six years in a small cao vit gibbon population at Bangliang, Guangxi, China. Results: In general, we found weak evidences for within-group contest or scramble competition in our two study groups, which we attribute to high spatial and temporal heterogeneity in the distribution of their important food species. Nevertheless, the larger of the two groups studied increased feeding time and group spread during lean periods, factors that may limit cao vit gibbon group size to a maximum of two breeding females. Relative to tropical pair-living gibbons, there is no evidence that cao vit gibbons travel farther or spend more time feeding, but they did consume more leaves and buds and less fruit and figs. Despite their highly folivorous diet, the average inter-birth interval is comparable to tropical gibbon populations, and the survival rate of infants and juveniles in our study groups is high. Conclusion: Cao vit gibbons do not suffer obvious costs in terms of feeding competition and reproductive success by living in bi-female groups, but within-group feeding competition may determine the upper the limit of cao vit gibbon group size to a maximum of two breeding females. These findings contribute to a growing body of evidence that bi-female grouping can be a stable grouping pattern of gibbons in certain habitats and further emphasize the flexibility of gibbon social organization. [ABSTRACT FROM AUTHOR]

Introduction: Species of the order Primates are highly gregarious with most species living in permanent heterosexual social groups. According to theory in socioecology maximum social group size is limited by rates of intra-group feeding competition and associated increases in travel costs. Unlike other hylobatids, which are predominantly pair living, cao vit gibbons (Nomascus nasutus), and two other species of crested gibbon (Nomascus spp.) living in northern seasonal forest, regularly exhibit larger bi-female groups. To better understand the ability of northern gibbons to live in stable bi-female groups, we examined food distribution, feeding competition and reproductive success over a period of six years in a small cao vit gibbon population at Bangliang, Guangxi, China., Results: In general, we found weak evidences for within-group contest or scramble competition in our two study groups, which we attribute to high spatial and temporal heterogeneity in the distribution of their important food species. Nevertheless, the larger of the two groups studied increased feeding time and group spread during lean periods, factors that may limit cao vit gibbon group size to a maximum of two breeding females. Relative to tropical pair-living gibbons, there is no evidence that cao vit gibbons travel farther or spend more time feeding, but they did consume more leaves and buds and less fruit and figs. Despite their highly folivorous diet, the average inter-birth interval is comparable to tropical gibbon populations, and the survival rate of infants and juveniles in our study groups is high., Conclusion: Cao vit gibbons do not suffer obvious costs in terms of feeding competition and reproductive success by living in bi-female groups, but within-group feeding competition may determine the upper the limit of cao vit gibbon group size to a maximum of two breeding females. These findings contribute to a growing body of evidence that bi-female grouping can be a stable grouping pattern of gibbons in certain habitats and further emphasize the flexibility of gibbon social organization.