Table 3. Direct CHW effect/contribution as recognised by study authors.

Study	CHW impact
West et al., 2011 [10]	“Lay health workers offers a promising vehicle for translation of evidenced-based obesity treatment in underserved areas”
Krukowski et al., 2013 [11] Krukowski et al., 2013 [12]	“A LHE [lay health educator] DPP translation in senior centers is effective in achieving weight loss at low cost and offers promise for the dissemination of this evidenced-based intervention” “Training LHE’s to disseminate evidenced-based interventions holds great promise for improving public health and access to effective care, particularly in medically underserved areas”
Katula et al., 2013 [17]	“A DPP administered through an existing community-based system and delivered by CHWs is effective at inducing significant long-term reductions in metabolic indicators and adiposity”
Islam et al., 2013 [19]	“…CHWs can facilitate support by serving as a bridge to the health care system and proving culturally- and linguistically- tailored health education”. …many participants felt connected to, and appreciative of the CHWs’ efforts, suggesting that CHWs serve a unique role in health promotion effort”
Duggan et al., 2014 [21]	“Bilingual CHWs removed linguistic barriers”
Koniak-Griffin et al., 2014 [22]	“Findings of this RCT support the feasibility and positive outcomes of implementing a promotora-facilitated Life Behaviour intervention in the community with overweight/obese Latinas”
Simmons et al., 2008 [24]	“Intensively treated participants would have had one or more unrecorded MCHW [Maori CHW] encounters and these may have had a significant effect” “The MCHW intervention was seen as key to the downstream intervention activities”
Staten et al., 2005 [42]	“The Pasos Adelante Program has demonstrated that an educational curriculum in conjunction with the support of promotoras can motivate people to healthy lifestyle behaviors”
Islam et al., 2014 [30]	“Participants reported positive feedback about the program and about the CHWs, particularly regarding the cultural congruence of CHWs and the strong connectedness of the intervention with community resources and cultural and religious norms and values”
Oba et al., 2011 [32]	“The research found that the health volunteers in each community were important for conducting the health promotion activities in their own villages”
Balagopal et al., 2012 [33]	“…that CHWs can provide advice on lifestyle modification and improve awareness of diabetes and CVD similar to allied health professionals in earlier studies… The CHWs were able to successfully empower the women to speak up at their meetings and instil them with confidence in their decision making abilities as related to their health and well-being. Using CHWs strengthened the links among project personnel, the community and existing community networks”
Philis-Tsimikas et al., 2014 [36]	“Participants appreciated the convenient community location, social support received from other participants and the promotoras”
Cherrington et al., 2015 [37]	“…peer delivered interventions may be particularly well-suited to the needs of immigrant women in newly emerging Latino communities”
Ruggiero et al., 2011 [38]	“For this project, the training, quality, professionalism and commitment of the CHWs that worked with program participants had an instrumental impact on high rates of retention and engagement of participants with project activities”
Sosa et al., 2013 [43]	“…evaluation results showed that promotoras were capable to deliver and retain participants in a lifestyle intervention program”
Kousar et al., 2015 [44]	“Here we confirm that CHV [community health volunteers] represent an effective tool for health promotion within culturally and linguistically diverse communities and have the capacity to incorporate evidence-based collection as part of their health education”
Cadzow et al., 2013 [40]	“Participants not only developed proficiency in discussing this important issue with their neighbors and peers, they also made important lifestyle changes that demonstrated their commitment to the cause and project” “The Neighborhood Health Talkers’ commitment to the program and embeddedness in their own communities resulted in an unpredicted reach to community residence”
Thompson et al., 2014 [31]	“This quasi-experimental study supports the hypothesis that Latino CHWs can use non-invasive diabetes and CVD screening tools with similar accuracy as a registered nurse”
Coppell et al., 2009 [45]	“A key factor underpinning the program was early involvement of CHWs, community members and local organizations and the use of local resources and talents so that the program would become embedded into everyday community life and sustainable in the long term.
Cohen & Ingram, 2005 [47]	“The curriculum for the family component, for example, was developed collaboratively between academics and promotoras who had never worked together in the past”
Whittemore et al., 2014 [50]	“…better understanding of the role of the CHW in the delivery of health programs is needed”