Social relationships and health related behaviors among older US adults

Health behaviors are a key determinant of population health and well-being. Smoking, excessive alcohol consumption, poor diet and physical inactivity are among the top 10 risk factors for death and disability in high and middle-income countries [1]. Health behaviors are important not only for children and young people, the traditional focus of many health education interventions, but also for adults and older people. Health damaging behaviors such as physical inactivity, poor diet, smoking and heavy alcohol consumption have been associated with an increased risk of disability and death in older people [2‐6]. Recently a French cohort study showed the cumulative effect of a combination of three unhealthy behaviors (smoking, low physical activity and low consumption of fruit and vegetables) on disability at the 12 year follow up [7]. Health behaviors also have an important role to play in maintaining good health and promoting successful aging. Sabia and colleagues demonstrated the protective effects of not smoking, moderate alcohol consumption, physical activity and eating fruit and vegetables on a range of positive cognitive, functioning and disease outcomes amongst the sample from the Whitehall II study [8].

Health behaviors are influenced by a complex array of inter related environmental, economic, social, psychological and biological factors [9]. One important determinant of behavior is the nature of the social environment. Most health behaviors are socially patterned in terms of their association with socioeconomic position. A good example of this is smoking where rates are higher in a step wise and consistent fashion as one descends the social hierarchy [10]. The nature, type and quality of social relationships also have a strong influence on patterns of behaviors [11, 12]. Most research on social relationships and health behaviors have been conducted amongst children and adolescents [13]. In particular an extensive literature has shown the influence, both positive and negative of peer relationships on adolescent health behaviors [14]. With adults several studies provide evidence that social relationships influence health behaviors [12]. For example, Berkman and Breslow showed in Alameda County that greater overall involvement in formal (e.g. religious organizations) and informal (e.g. friends and family) social ties was associated with more positive health behaviors over a 10 year period [15]. Being married [16], having a family [17] and involvement in religious organizations [18] have all been associated with health promoting behaviors. Social relationships however also carry the potential for encouraging health damaging behaviors such as problem drinking [19]. Individuals with poor social relationships are more likely to smoke, engage in low levels of physical activity and have a poor diet [20‐22]. The association between poor social relations and adverse health behaviors appears to be strongest amongst lower socioeconomic groups [23]. Relatively little research has however focused upon the association between social relationships and health behaviors amongst older people [24]. US studies have shown that older people with strong social relationships had better nutrition [25], increased use of mammography [26] and more frequent attendance at a dentist [27]. Older Americans with limited social networks have also been shown to have higher levels of alcohol misuse and physical inactivity [28]. In the UK oral health behaviors were associated with social isolation in a sample of older adults [29].

Patterns of behavior and the nature of social relationships are both dynamic constructs that change across the life course [12]. It is therefore important to explore in detail the association of social relationships with health behaviors at different points in the life course. Previous studies have assessed only certain aspects of social relationships with a limited range of health behaviors. This study therefore assessed the relationship between social networks and social support with four health related behaviors, namely alcohol use, smoking, physical activity and attendance at the dentist amongst a nationally representative sample of older Americans. Further, we tested whether the availability of social support played a mediating role in the associations between social networks and the above behaviors.

We analyzed data from the US National Health and Nutrition Examination Survey (NHANES), combining three waves of data that were collected in 1999/2000, 2001/2002 and 2003/2004. NHANES is a rich dataset which contains information on respondent’s general health and self-reported health behaviors, validated instruments measuring social networks and support, as well as a range of socio-demographic background variables. The survey used a stratified, multistage design to obtain a representative sample of the US non-institutionalized population, over-sampling older people, as well as ethnic minority groups. A detailed description of the survey methodology and sampling procedure has been published elsewhere [30, 31]. Because the study aim was to examine associations between social relationships and health related behaviors among older people, we restricted the analysis sample to those aged 60 years and over (the same cut-off used in NHANES for oversampling older people), resulting in a sample size of 4,014 participants. The NHANES survey protocol was approved by the National Center for Health Statistics Research Ethics Review Board. All participants provided written informed consent.

A total of 4,014 participants aged 60 years and older were included in the analysis for whom information was complete. The unweighted mean age of the sample population was 71.7 years (Table 1). In this sample of older Americans, 57% of men and 46% of women had engaged in physical activity over the past 30-days. About 65% of participants had visited a dentist within the past two years, and this was the same for both sexes. Smoking was reported by 14% of men and 11% of women, while 15% of men and 14% of women were classified as heavy drinkers. All examined behaviors appeared to be less prevalent in older age groups. Respondents who were married or living with a partner, had a higher number of close friends and access to sufficient emotional support were more likely to report at least moderate physical activity, to have been seen by a dentist and to be non-smokers in the bivariate analyses. Heavy drinking was also more prevalent among those not living with a partner, however there were no clear associations with the number of close friends and availability of emotional support. The distribution of physical activity, dental visits and smoking followed marked social gradients, with people on higher incomes and a higher level of education being more likely to engage in beneficial behaviors (i.e. physical activity and dental visits) and less likely to be smokers. Heavy drinking was however slightly more prevalent among more affluent respondents and those who were educated beyond high school.

This study has shown that social relationships were independently associated with a range of health behaviors in a national sample of older US adults, even after adjusting for the effect of broad demographic and socioeconomic determinants. In particular, being widowed or divorced/separated was significantly associated with being a current smoker, and amongst older men, with being a heavy drinker. Single older women were also more likely to be heavy drinkers. Widowed older people were less likely to attend a dentist. In addition, older people with more close friends more commonly engaged in physical activity. Furthermore, the availability of emotional support did not mediate any of the above associations, but emotional support was associated with physical activity but none of the other behaviors assessed. Access to financial support through social relationships was not related to any of the examined health behaviors.

An extensive body of research has demonstrated the effect of social relationships on health and mortality [43, 44]. One of the potential pathways linking social relationships to health is via behavioral factors. However, very few studies have investigated the association between social relationships and health behaviors amongst older people. Frongillo et al. [25] showed that older people with strong social ties had better dietary behavior [25]. In a population of older black Americans, higher levels of social support were associated with attendance at cancer screening services [26]. We are not aware of any other studies that have assessed a combination of health behaviors and their association with both measures of social support and social networks in a sample of older people.

Our findings on the importance of marital status on health behaviors are in accordance with previous reports amongst younger and middle aged adults linking marital dissolution with health compromising behaviors. Longitudinal studies have shown that marital termination, either due to the death of a spouse or divorce, were associated with tobacco and alcohol consumption [45‐47]. It is likely that changes in both social support and stress levels are key factors in explaining this link [45]. Smoking and excessive drinking are both related to high levels of stress [48, 49] and low levels of social support [50]. Indeed support from a partner may act as a buffer against the harmful effects of stress, and thereby lead to reductions in tobacco and alcohol use [51].

Previous studies have shown that amongst adults, poor social relationships [22] and with older people, limited social networks [28] were both associated with low levels of physical activity. Our results support these findings and highlight the importance of social relationships on physical activity. Older individuals with well-developed and supportive social relationships may be encouraged by their peers and family to adopt and maintain physical activity and may have more information to access local services and amenities.

The associations between social relationships and the three behaviors physical exercise, dental visits and smoking were attenuated after adjusting for socio-economic status, and in the case of dental visits the association was no longer statistically significant. This suggests that those who were poorer and less educated also tended to have smaller friendship networks and were less likely to live with a partner. As expected, there was no attenuation of the results for heavy drinking, which showed a reverse social gradient, i.e. was more common among the more advantaged. Although we observed social gradients in relation to physical exercise, dental visits and smoking, the availability of financial support was not related to any of the examined behavioral outcomes. It is possible that financial support from relatives and friends is given only in the event of an emergency, and is not enough to alleviate the effects of poverty and limited income on patterns of health behaviors.

This study used a large nationally representative sample of US older people, included a range of both health promoting and health damaging behaviors and the detailed analysis controlled for a diverse spectrum of potential confounders. However it is important to acknowledge the limitations of this study. Social support and social networks were only partially assessed due to lack of relevant data, i.e. validated instruments, in NHANES. We only assessed perceived emotional support and did not include any measures of informational and appraisal dimensions of social support. The assessment of social networks covered the size of the networks but did not assess the intensity or quality of social contacts [52]. We also acknowledge that the social network and social support variables could have been categorised in various different ways. For example, it is possible that people with no close friends are very different from people with four close friends. However, having zero friends was very rare in our sample (reported by only 3.7% of all participants). As there is no other cut-off point for this variable that could be conceptually justified, dividing the sample into tertiles was an alternative. Sensitivity analyses using “number of friends” as a continuous variable produced consistent results, i.e. a modest statistically significant association with physical activity but not with the other behaviors. Further to this, we also tested whether dividing the variable “lack of emotional support” into three categories (having someone to provide support plus having received enough support; having someone to provide support but could have used more support; and having no one to provide support) would influence the results, which was not the case. As for the binary variable, the only significant association was with physical activity, with very similar prevalence ratios for the categories “not enough support” and “no support”.

The behavioral outcomes were all assessed through self-report measures which are subject to bias and under reporting. Physical activity in particular is notoriously difficult to assess accurately. NHANES uses its own physical activity questionnaire (PAQ), which although containing an extensive array of questions, cannot be considered to be a validated measure. Our study assessed dental visits as an indicator of health-service use but did not examine the use of other health services, for which associations might be different. Both the social relationship measures and behavioral outcomes were recorded cross-sectionally and did not assess the dynamic nature of these constructs [53]. In the analysis although we adjusted for a range of important covariates, residual confounding may still be an issue. Finally, the cross sectional study design limits any consideration of causal relationships. Indeed it is possible that the association between social relationships and behaviors is due to reverse causation – people who engage in health compromising behaviors may not be able to establish long term stable relationships and older people who smoke and drink heavily might become socially isolated because these behaviors are considered socially undesirable [53].

In conclusion, this study has shown that social relationships were independently associated with a diverse range of health behaviors amongst a nationally representative US sample of older people. The findings of this study have important implications for public health. Our results provide some evidence that behavioral factors are on the pathway linking social relationships and health. Therefore strengthening and developing social relationships amongst older people should be a priority in health promotion. More interventional studies are however needed to assess if strengthening social relationships would have a significant impact on health behaviors, and ultimately health outcomes amongst older people.