摘要：Objectives. We investigated whether exposure to negative aspects of close relationships was associated with subsequent increase in body mass index (BMI) and waist circumference. Methods. Data came from a prospective cohort study (Whitehall II) of 9425 civil servants aged 35 to 55 years at baseline (phase 1: 1985–1988). We assessed negative aspects of close relationships with the Close Persons Questionnaire (range 0–12) at phases 1 and 2 (1989–1990). We measured BMI and waist circumference at phases 3 (1991–1994) and 5 (1997–1999). Covariates at phase 1 included gender, age, marital status, ethnicity, BMI, employment grade, smoking, physical activity, fruit and vegetable consumption, and common mental disorder. Results. After adjustment for sociodemographic characteristics and health behaviors, participants with higher exposure to negative aspects of close relationships had a higher likelihood of a 10% or greater increase in BMI and waist circumference (odds ratios per 1-unit increase 1.08 [95% confidence interval (CI) = 1.02, 1.14; P = .007] and 1.09 [CI = 1.04, 1.14; P ≤ .001], respectively) as well as a transition from the overweight (25 ≤ BMI < 30) to the obese (BMI ≥ 30) category. Conclusions. Adverse social relationships may contribute to weight gain. Obesity is a major public health concern because it is associated with numerous ill health conditions such as type 2 diabetes, coronary heart disease, hypertension, stroke, and certain forms of cancer. 1 Obesity rates have rapidly increased to epidemic proportions. In England, for example, 24% of men and 25% of women are obese (body mass index [BMI, defined as weight in kg divided by height in m2] ≥ 30). 2 The interplay among multiple factors—genetic factors, factors stemming from obesogenic environments, and individual, and cultural factors—is seen to be behind the obesity epidemic. 3 However, increasing evidence suggests that social relationships may also play a role in determining weight gain. Stress associated with poor-quality relationships may contribute to weight gain via various mechanisms. Negative aspects of close relationships may induce negative feelings, 4 which can increase physiological arousal either through activation of the hypothalamic–pituitary–adrenal axis or through the fight-or-flight response and the secretion of adrenal medullary hormones. 5 Eating high-fat and high-carbohydrate caloric content “comfort food” may reduce biological stress system activity and the concomitant negative emotions. 6 Some evidence also suggests an association between chronic life stress and a greater preference for energy- and nutrient-dense foods, namely those that are high in fat and sugar. 7 In addition, there may be further effects via other unhealthy coping mechanisms such as physical inactivity. Childhood adversities related to close relationships, such as physical abuse, verbal abuse, humiliation, neglect, strict upbringing, physical punishment, conflict, or tension, have been associated with an increased risk of obesity in adulthood. 8 However, limited and somewhat inconsistent evidence exists on the impact of negative aspects of close relationships in adulthood. One study revealed that heavier women had lower quality romantic relationships. 9 Poor marital quality has also been associated with a higher risk of metabolic syndrome 10 and obesity 11 in women. Strain in relations with family but not with one's spouse or partner was associated with weight gain in women with high initial BMI. 12 In addition, some studies have revealed an association between reports of insufficient social support and increased risk of obesity, 13 , 14 but other studies suggest no such association. 15 With a few exceptions, 10 – 12 the evidence is cross-sectional or derived from short follow-ups. Such data leave open the possibility of reverse causality (i.e., obesity negatively influencing close relationships). Because the development of obesity has a relatively long induction period, it is plausible that prolonged exposure to problems in social relationships affects weight more than do short-term problems. Moreover, it might be more informative to look at weight gain rather than obesity status at 1 time point. We are not aware of previous studies examining the association between negative aspects of close relationships and weight gain. In addition, most of the earlier studies did not assess waist circumference, a measure of central obesity. Waist circumference is probably a better indicator of health risk than is BMI alone, especially when used in combination with BMI. 16 In this study using data from the Whitehall II cohort of British civil servants, we investigated the extent to which exposure to negative aspects of close relationships was associated with subsequent weight gain, as indicated by increase in BMI and waist circumference over a long follow-up period.
