The experience of the BPRHS illustrates the challenges of conducting research in a Hispanic ethnic subgroup, and demonstrates the disparities faced by this community. The study has recruited 1,500 older adult Puerto Ricans, but considerable effort to obtain completed interviews has been required. Several studies have reported difficulties in recruiting minority research participants [65
], especially Latino men [20
]. It is possible that with door-to-door enumeration, women are more likely to be at home and therefore more frequently approached. They also appear to be more willing to participate than men, although this was not statistically significant in this study.
After enumeration, re-contacting individuals posed significant challenges. A key factor in the eventual success in locating individuals was recording information of close contacts. However, in many cases, field staff needed to return to the neighborhood to locate the individual. Recruitment completion was further delayed by frequent cancellations of appointments. These challenges led to loss of staff time and effort, and greatly increased the study cost over that originally estimated. Similarly, Eakin et al. reported the need to hire extra phone staff in order to increase retention of Latinos [21
]. Interestingly, main reasons for cancellation included medical appointments and illness of the participant or a relative, which is consistent with the observed high prevalence of disease, and the sharing of burden among socially connected individuals.
Mistrust of scientific investigations is frequently reported as a major barrier to recruitment in minority participants [65
]. Several strategies were used to facilitate recruitment, including employing a bilingual and ethnically diverse staff, and partnering with a local community organization. Recruitment at community events increased the study's visibility and involvement in the community, and enabled staff to obtain updated contact information for enrolled participants. Use of the media also reinforced the legitimacy of the study. Because the total community is relatively small, receptivity increased over time.
Efforts to keep the participants' trust and engagement in the study have helped sustain a high retention during two-year follow-up. As the study moves forward, questions on progression and mechanisms of diseases may be answered more accurately. Little is known about the environmental influences and life events of elderly Puerto Ricans living in the US; thus, possible cohort effects require further consideration. The wide age range of this group, constant migration patterns to/from Puerto Rico, limited social networks, and low residential stability may limit assumptions about cohort effects.
As with most epidemiological studies, selection bias could be operating in this study. For example, as those declining participation in the study were living in the US longer that those participating, possible selection bias by acculturation, which is highly correlated to years living in the US, may occur. Still, there was low acculturation in this sample, suggesting that such bias may not exist. The door-to-door recruitment method may have introduced selection bias, as participants recruited with this method, who comprised the majority of this cohort, had somewhat differing characteristics than those recruited through community events. The study followed exhaustive protocols to identify participants at home, making a great effort to expand recruitment with various strategies; the addition of participants from community approaches likely improved the representativeness for the study, as individuals who may have been seldom at home were included. Notably, the majority of Puerto Ricans aged 45-75 years identified by Census tracts, lived in neighborhoods and communities from which the study recruited.
Data from the 2000 Census show that, of Puerto Ricans aged 45-75 years living in high-density Hispanic blocks in Boston, 75% were 45-59 years, and 25% were 60-75 years [69
]. Overall, the sample of this study was somewhat older, with about two-thirds in the younger and one-third in the older age range. When stratified by recruitment method, the age distribution more closely resembled that of the Census findings for those approached through flyers, community events or referrals (70% aged 45-59 years), whereas door-to-door recruitment yielded 60% in the younger category. Education levels for study participants were similar to those identified for Census data for Puerto Ricans in Boston; yet the study had fewer women in the older group that held a current job relative to 2000 Census data, while a greater number of men in the older age category reported working in this sample. This difference may be partly due to economic changes that have occurred since the year 2000. This sample of 1,500 individuals represents a fairly large proportion (15%) of the 10,241 Puerto Ricans in this age range living in the towns that we recruited from, as of 2000. Although this may suggest that a representative sample for this population was likely captured, the limited areas and approaches for recruitment may have reduced representativeness. Still, the results should be reasonably generalizable to similar communities of Puerto Rican adults living in high density urban areas in the US.
Hispanic subgroups are often combined together in health research; however, this practice may obfuscate important differences in subgroups. Though limited, accumulating studies provide evidence that health disparities differ considerably by subgroup [7
]. The results of this study support observations that Puerto Ricans on the US experience considerable health disparities which exceed those reported for NHW or other Hispanic subgroups, including the more commonly studied Mexican Americans. The prevalence of physical and cognitive disability, type 2 diabetes, obesity, depressive symptomatology, hypertension, and self reported heart disease were higher in this sample, in relation to published reports for similarly-aged Mexican Americans [3
]. Notably, the high prevalence of these conditions was observed even for those in the younger age category. For example, the prevalence of obesity in this sample of Puerto Rican men and women, aged 45-59 years, (43% and 60.5%, respectively) was higher than that reported by NHANES 2001-2004 for Mexican Americans in the same age range (36.3% and 52.2%, respectively) [74
]. One caveat of this type of comparisons is that differences in survey methodology and year of data collection may affect the interpretation of the comparison.