Risk factors for night sweats and hot flushes in midlife: Results from a prospective cohort study

OBJECTIVE: This study aims to identify social, lifestyle, and reproductive history risk factors for night sweats (NS) only, hot flushes (HF) only, and both NS and HF. 

METHODS: Risk factors and symptoms among 10,454 participants of the Australian Longitudinal Study on Women's Health who were aged 45 to 50 years in 1996 were measured at baseline and 3-year intervals (surveys 2-6) for 15 years. Multinomial logistic regression analyses were performed. 

RESULTS: Compared with neither symptom, both symptoms together were reported less often by highly educated women (odds ratio, 0.61; 99.9% CI, 0.50-0.74), but more often by women who were heavier (odds ratio, 1.23; 99.9% CI, 1.08-1.40), were current smokers (odds ratio, 1.31; 99.9% CI, 1.09-1.56), were high-risk drinkers (odds ratio, 1.44; 99.9% CI, 1.10-1.89), were perimenopausal (odds ratio, 6.57; 99.9% CI, 5.52-7.82) or postmenopausal (odds ratio, 4.74; 99.9% CI, 4.00-5.63), had gained weight (odds ratio, 1.15; 99.9% CI, 1.01-1.31), or had premenstrual tension (odds ratio, 1.86; 99.9% CI, 1.48-2.34), than by women without these characteristics. HF only was reported less often by highly educated women (odds ratio, 0.73; 99.9% CI, 0.59-0.90), but more often by perimenopausal (odds ratio, 3.58; 99.9% CI, 2.95-4.35) or postmenopausal (odds ratio, 2.97; 99.9% CI, 2.47-3.57) women and by those with premenstrual tension (odds ratio, 1.60; 99.9% CI, 1.25-2.04). Finally, NS only was reported more often among current smokers (odds ratio, 1.55; 99.9% CI, 1.11-2.19), high-risk drinkers (odds ratio, 1.76; 99.9% CI, 1.04-2.97), perimenopausal women (odds ratio, 1.53; 99.9% CI, 1.14-2.06), those with diabetes (odds ratio, 1.91; 99.9% CI, 1.08-3.35), those with premenstrual tension (odds ratio, 1.67; 99.9% CI, 1.09-2.56), or those of early age at first pregnancy (odds ratio, 1.45; 99.9% CI, 1.05-1.99). 

CONCLUSIONS: The presence of both symptoms is associated with social, behavioral, and menstrual factors. Some differences in risk factors among women who report only one symptom or both symptoms are observed, suggesting a slightly different etiology for each.