For many people, the family is a major mechanism of influence in effecting change both in other family members and in themselves (
6). The concept of family has many connotations. For the purposes of this review we believe "family" should be defined inclusively rather than exclusively, similar to Medalie and Cole-Kelly's (
7) description of a family as a complex of configurations representing census, biologic, household family, and functional family connections. We add the observation that family includes a parent-child connection and a sharing of responsibilities that functions for the welfare of both the individual members and the family unit.
The reciprocal nature of the adult-child relationship merits strong attention as a means of influencing health behavior of both children and adults (
8). Efforts to achieve and maintain weight loss are more successful with family involvement (
9). Positive eating behavior changes last longer if interventions are aimed at family rather than individuals' attitudes and habits (
10).
It has been well established that physical, normative, and social characteristics of the family influence adoption and maintenance of health-promoting behavior. Family dynamics including family rules, emotional support, encouragement, reinforcement from other family members, and family member participation are important determinants of the family's health-behavior patterns (
6). Viewed in this context, the family system is a major determinant of how and whether families engage in health-promoting physical activities (
5).
Because most health behaviors are initiated in childhood, influencing the health behavior of individuals when they are children is reasonable and practical (
10). It is well recognized that eating habits developed in childhood and adolescence may be difficult to change. Consequently, effecting behavior change when individuals are children is critical. The family shapes children's dietary intake and eating habits (
11-
13) and their physical activity patterns (
14). Family influences also are present in the development and control of weight problems in children and adults (
15-
20).
The family is a highly suitable target for health promotion intervention because it provides many options and opportunities to communicate positive health behavior messages and change family member attitudes and behavior. Within the family context, meal planning, food shopping, meal preparation, eating, snacking, family recreation, and sedentary behaviors are all opportunities for intervention (
16). The family provides the primary social learning environment for children and the primary setting for exposure to food choices, eating habits, and involvement in opportunities for play and other physical activity (
21). Parental health behavior guides the development of health practices in children, and children can influence these same behaviors of their parents and siblings (
10,
22-
24).
Reciprocal reinforcing relationships among family members are important for acquiring and maintaining new behaviors (
25). The family is an ideal mutually reinforcing environment in which healthy behaviors can be introduced, accepted, and maintained (
26). Epstein et al (
19) reported findings from a series of weight loss interventions targeting adults and their children with different conditions of reinforcement of parents and the children, for the children only, or for general family participation. Results revealed that reinforcing weight loss for both the parent and the child produced the greatest weight loss over a 5-year period. The authors concluded that the relationship between parent and child weight loss can serve as a reciprocal reinforcer for changes in diet and other weight loss–related behaviors.
Family-based behavioral obesity treatment programs are among the most effective for combating pediatric obesity. Wrotniak et al (
26) reported that concurrent treatment of children with their obese parents tends to result in positive change for both, though the effects tend to be greater and longer lasting for children. This may be the result of more changes to the eating and activity environment in the home or to more healthy diet and exercise role modeling of the parents.
Family as a unit of measurement
Analyzing the family as a unit merits consideration (
5,
27-
30). Blackwell and Reed (
27) argue that a family-level analysis was more appropriate to accurately test the concepts and propositions of the power-control theory. They reasoned that because the family environment encompasses both shared and nonshared environmental influences and because of the differential effects of dyadic relationships within the family unit, analysis at the family level is appropriate when there is interest in the combination of effects of these relationships. Blackwell and Reed concluded that family-level data allowed them "to devise more methodologically appropriate measures and theoretically informative models than can be constructed with individual-level data" (p. 396). They further argued that family-level data provide control for "potential sources of 'shared environmental' characteristics" (p. 397).
Bonomi et al (
28) suggested that to avoid over- and underestimations of health intervention cost effectiveness, a family-level assessment (eg, family functioning, family choices) is more appropriate. Because illness seldom affects a single individual but often affects the overall functioning of a family as a unit, determining the well-being of and costs borne by multiple family members is likely to represent a more accurate view of resource allocation. They suggest that a family well-being model, one that encompasses individuals within a family, relationships among those individuals, and the aggregation of the individuals constituting the unit, forms a good basis for addressing health at the family level. Their model is derived from systems theory, which posits that relationships between individuals and their family change over time in response to input and events that they experience alone and together (
31).
Family as the unit of health promotion intervention
Eating dinner together as a family has been associated with healthy weight and consumption of healthy foods (
32-
35). Gillman et al (
33) found that intake patterns among children and older adolescents when eating dinner with their parents resulted in consumption of more fruits and vegetables, less fried food and soda, and less saturated and
trans fat; lower glycemic loads; and more fiber and more micronutrients from food. Aside from the social context of the family, health similarities among family members make the family a good candidate for being the "unit" of health promotion intervention (
36). In addition to the influence of genetic factors, fitness and health can be linked to the familial environment. Studies of eating habits (
36,
37), exercise routines (
38), food and activity preferences (
39), blood pressure levels (
40-
42), body weight (
43,
44), body composition and adiposity (
45,
46), and physical activity (
47) have found that family members tend to share these characteristics.
Families as a Support Context
Familial social support has been well demonstrated to be a key factor for promoting and sustaining health behavior change (
2,
48-
50). Spousal support has been identified as an important factor influencing weight reduction among obese women with type 2 diabetes (
18). Familial support has been reported effective in producing health-promoting behaviors among patients with cardiovascular disease (
51) and for chronically ill family members achieving physical activity guidelines and practicing better dietary behaviors (
52). Finally, family support consistently correlates positively with physical activity levels (
49,
53,
54).
Ethnic and sociocultural considerations in using families as a source for health promotion
Because of traditional values, social networks, patterns of inter- and intrafamilial support, food preferences, and recreational choices, ethnic and sociocultural factors must be considered. Food habits are deeply rooted in a family's culture, which represents both their ethnic and community identity (
55). Families must contend with outside influences that affect the availability of preferred foods and with the introduction of new foods and different ways of food preparation. As a result, the change in dietary practices, at least among families with children, often occurs at the family level; most family members adopt new food choices and eating habits. This process is evident among immigrant groups as they assimilate into a new culture. As families become more acculturated, traditional foods are consumed less often.
It is widely recognized that ethnic and sociocultural influences create differences in health behaviors. For example, research has shown that Hispanics tend to be less knowledgeable about cardiovascular risk factors, prepare more of their foods by frying, and engage in less physical activity than whites (
56). Members of ethnic groups respond differently to health promotion messages and interventions. Nader et al (
57) found that white families reported more change in their dietary and physical activity habits than did Mexican American families after an intervention to reduce cardiovascular risk among school children. The use of an ecological perspective as a means for understanding maintenance and change in dietary practices among immigrant ethnic groups is also applicable to the family unit.
Hispanic families are strongly family-centric, which makes the influence of the family both a facilitator and a barrier for participation in physical activity. For many Hispanic wives and mothers, both the family and care of the home comes before self (
58). To overcome this barrier, Hispanic immigrants feel that activities that involve the family, particularly their children, can provide them the necessary incentives and opportunities to be physically active (
58). Thus, family-based interventions developed within the cultural context of the target audience (taking cultural considerations into account) may result in more effective dietary and physical activity behavior change.