The effect of weight change on nursing care facility admission in the NHANES I Epidemiologic Followup Survey

Abstract

Data from the first National Health and Nutrition Examination Survey Epidemiologic Followup Survey were used to examine whether weight change was associated with an increased relative risk of nursing care facility admission. Hazard ratios were calculated with Cox proportional hazards models and stratified by overweight status at baseline. Moderate and large weight loss was associated with an increased risk of nursing care facility admission in overweight and non-overweight subjects. Large weight gain was associated with an increased relative risk in only overweight subjects. In the process of functional decline that results in nursing care facility admission, weight loss may be a sign of acute illness, starvation, or aging. Preventing weight loss may help delay this process of decline. In overweight subjects, preventing weight gain may also be important in delaying this process of decline.

Introduction

Large weight loss and large weight gain have been associated with greater morbidity, mortality, functional limitation, and greater health care charges [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19]. Given that weight gain and weight loss have been strongly associated with aspects of declining functional status, both may be risk factors for earlier nursing home utilization. Previous work has shown that weight loss is a risk factor for nursing home use; however, a relationship with weight gain has not been demonstrated [4], [20]. An identification of the effect of weight loss and weight gain on nursing home placement would facilitate a further understanding of the role of weight change in future health care use.

The reasons that weight gain and weight loss are related to nursing home utilization probably result from different mechanisms. Studies have shown weight gain to be associated with comorbidities such as diabetes mellitus type II [3], [7], [12], hypertension [13], coronary heart disease [2], [10], and decreased physical function and vitality [8], [19]. The process of functional decline associated with weight gain leads individuals to be placed in nursing care facilities [21]. However, weight loss has been closely tied to the aging process and may be a result of the disability process [22]. Findings from mostly cross-sectional studies suggest that individuals gain weight until they reach their fifties or sixties, at which time they begin to lose weight [23], [24], [25]. Therefore, to investigate the full spectrum of weight change, study populations need to include a greater age range. Furthermore, the few studies that have focused on weight dynamics have largely ignored initial weight or body mass index (BMI) status. Several studies have shown initial BMI to have a mediating effect on the relationship between morbidity and weight change [16], [17], [26], [27], [28].

Although previous work has found obesity and weight loss to be associated with a greater hazard of nursing home placement, an association between weight gain and nursing care facility placement has not been demonstrated [4], [20], [29]. We focused on the total effect of longer-term weight change among middle-aged and older adults on nursing home placement. Using a national sample of US adults, we examined the association between weight measurements taken approximately 10 years apart and the relative risk of subsequent nursing home admission. We also examined whether the effect of weight change on nursing home admission varies by initial weight status.