Middle age

Abstract: Objective and design: To relate UK national trends since 1950 in smoking, in smoking cessation, and in lung cancer to the contrasting results from two large case-control studies centred around 1950 and 1990. Setting: United Kingdom. Participants: Hospital patients under 75 years of age with and without lung cancer in 1950 and 1990, plus, in 1990, a matched sample of the local population: 1465 case-control pairs in the 1950 study, and 982 cases plus 3185 controls in the 1990 study. Main outcome measures: Smoking prevalence and lung cancer. Results: For men in early middle age in the United Kingdom the prevalence of smoking halved between 1950 and 1990 but the death rate from lung cancer at ages 35–54 fell even more rapidly, indicating some reduction in the risk among continuing smokers. In contrast, women and older men who were still current smokers in 1990 were more likely than those in 1950 to have been persistent cigarette smokers throughout adult life and so had higher lung cancer rates than current smokers in 1950. The cumulative risk of death from lung cancer by age 75 (in the absence of other causes of death) rose from 6% at 1950 rates to 16% at 1990 rates in male cigarette smokers, and from 1% to 10% in female cigarette smokers. Among both men and women in 1990, however, the former smokers had only a fraction of the lung cancer rate of continuing smokers, and this fraction fell steeply with time since stopping. By 1990 cessation had almost halved the number of lung cancers that would have been expected if the former smokers had continued. For men who stopped at ages 60, 50, 40, and 30 the cumulative risks of lung cancer by age 75 were 10%, 6%, 3%, and 2%. Conclusions: People who stop smoking, even well into middle age, avoid most of their subsequent risk of lung cancer, and stopping before middle age avoids more than 90% of the risk attributable to tobacco. Mortality in the near future and throughout the first half of the 21st century could be substantially reduced by current smokers giving up the habit. In contrast, the extent to which young people henceforth become persistent smokers will affect mortality rates chiefly in the middle or second half of the 21st century.

Abstract: The effects of age on the prevalence of sleep apnea in the general population remain unclear, because previous studies have focused on specific populations. The effects of age on the severity of apnea are unknown. This study was based on a two-stage general random sample of men (aged 20 to 100 yr), consisting of a telephone survey (n = 4,364) and a sleep laboratory evaluation of a survey subsample (n = 741). Obstructive sleep apnea (OSA), based on both sleep laboratory and clinical criteria (apnea/hypopnea index [AHI] > or = 10 and the presence of daytime symptoms) was found in 3.3% of the sample, with its maximum prevalence in the middle age group (45 to 64 yr). Also, based solely on laboratory criteria, the prevalence of OSA (obstructive AHI > or = 20) showed an age distribution similar to that of OSA diagnosed by laboratory and clinical criteria. The prevalence of any type of sleep apnea (central and obstructive) increased monotonically with age. However, central apnea appeared to account for this monotonic relationship with age. Severity of sleep apnea, as indicated by both number of events and minimum oxygen saturation, decreased with age when any sleep apnea criteria were used and when controlling for body mass index (BMI). The study shows that the prevalence of sleep apnea tends to increase with age but that the clinical significance (severity) of apnea decreases. On the basis of these findings, the sleep laboratory criteria used for diagnosis of sleep apnea should be adjusted for age.

Abstract: Age differences in emotional experience, expression, and control were investigated in 4 studies. A community sample of 127 African Americans and European Americans (ages 19-96 years) was used in Study 1; a community sample of 82 Chinese Americans and European Americans (ages 20-85 years) was used in Study 2; a community sample of 49 Norwegians drawn from 2 age groups (ages 20-35 years and 70+ years) was used in Study 3; and a sample of 1,080 American nuns (ages 24-101 years) was used in Study 4. Across studies, a consistent pattern of age differences emerged. Compared with younger participants, older participants reported fewer negative emotional experiences and greater emotional control. Findings regarding emotional expressivity were less consistent, but when there were age differences, older participants reported lesser expressivity. Results are interpreted in terms of increasingly competent emotion regulation across the life span.

Abstract: Objective To evaluate any association between obesity in middle age, measured by body mass index and skinfold thickness, and risk of dementia later in life. Design Analysis of prospective data from a multiethnic population based cohort. Setting Kaiser Permanente Northern California Medical Group, a healthcare delivery organisation. Participants 10 276 men and women who underwent detailed health evaluations from 1964 to 1973 when they were aged 40-45 and who were still members of the health plan in 1994. Main outcome measures Diagnosis of dementia from January 1994 to April 2003. Time to diagnosis was analysed with Cox proportional hazard models adjusted for age, sex, race, education, smoking, alcohol use, marital status, diabetes, hypertension, hyperlipidaemia, stroke, and ischaemic heart disease. Results Dementia was diagnosed in 713 (6.9%) participants. Obese people (body mass index ≥ 30) had a 74% increased risk of dementia (hazard ratio 1.74, 95% confidence interval 1.34 to 2.26), while overweight people (body mass index 25.0-29.9) had a 35% greater risk of dementia (1.35, 1.14 to 1.60) compared with those of normal weight (body mass index 18.6-24.9). Compared with those in the lowest fifth, men and women in the highest fifth of the distribution of subscapular or tricep skinfold thickness had a 72% and 59% greater risk of dementia, respectively (1.72, 1.36 to 2.18, and 1.59, 1.24 to 2.04). Conclusions Obesity in middle age increases the risk of future dementia independently of comorbid conditions.