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PubMed1978

What will 1984 be like? Socioeconomic implications of recent twists in age structure.

Since 1940, under conditions of restricted immigration and high and sustained growth in aggregate demand, shifts in the relative number of younger versus older adults have had a pervasive impact on American life. Before 1960, younger males were in increasingly short supply and their relative economic position substantially improved; after 1960, the opposite was true. Since the early sixties, as the relative condition of young adults has deteriorated, marriage has been increasingly deferred and fertility reduced. The labor force participation of young women has risen at above average rates, and that of older women has risen at below average rates. Changes in the age structure of the working age population have also contributed to a combination of rising unemployment and accelerating inflation. Cohort divorce rates, suicide among young males, crime rates, and political alienation have worsened. The rise in college enrollment rates has been interrupted, and SAT scores have declined. In contrast, in the period 1940-1960, changes in these various magnitudes were typically of a more favorable sort. The United States is now at the start of a new period of growing scarcity of young adults as a result of the birth rate decline that set in after 1960. This implies that the 1980s will see a turnaround or amelioration in a wide variety of these social, political, and economic conditions, some of which have been taken as symptomatic of a hardening social malaise.

Adult↗
PubMed1980

Impact of the national family planning program on fertility in rural Korea: a multivariate areal analysis.

The impact of the previous three years' input of the national family planning program on 1975 fertility levels in rural Korea was assessed using multivariate areal analysis techniques. Program input had a measurable negative effect on fertility, but the magnitude of the effect was lower than that of nonprogram factors. Holding availability of nonprogram methods of fertility limitation constant strengthened the impact of program input. It was suggested that the effect of the national program was statistically obscured by the selective concentration of program input in high-fertility, physician-poor areas.

Adult↗
PubMed1994

Brain and other nervous system tumours.

Interpretation of time trends in incidence rates for cancers of brain and other and unspecified parts of nervous system is complicated by variation in registration efficiency over time and place, statistical instability of rates, changes in the ICD classification of the tumours, variation in registration practice for the benign and unspecified tumours over time and changes in methods of diagnosis. The reader will undoubtedly have the impression that in this chapter there are too many differences in the content of the data over time and place to have confidence in any of the conclusions drawn. To derive a well documented and sustainable assessment on secular trends will require an international collaborative study collecting incidence data for the malignant, benign, uncertain and unspecified tumours of the brain and other parts of the nervous system by histology and by method of diagnosis. By providing a separate rubric for the meninges, the 10th Revision of the ICD (WHO, 1993) should--combined with the morphology rubrics of the second edition of the International Classification of Diseases-Oncology (Percy et al 1990)--make such an endeavour somewhat easier. The data presented above nevertheless suggest that, as for several other cancer sites, on the whole there has been a slow overall increase in the incidence of brain and other and unspecified nervous system neoplasms on the order of 1-2% per year over the past 30 years. Increases appear to have been greater in older people. The extent to which these increases are due to the unquestioned improvements in methods and precision of diagnosis is not clear. Birth cohort data suggest that in recent years, this influence may have been greatest for those birth cohorts born prior to 1900, and this effect is unlikely to disappear until cohorts born about 1910-1920 have passed on. There is currently little evidence to support the contention that the recent increase in older people cannot be largely explained by improvements in diagnostic methods, wider access to medical care and more intensive investigation. Further work is needed.

Adult↗
PubMed1995

Fertility of the over forties.

This article focuses on women aged forty and over in England and Wales. It identifies changes in fertility patterns in the late childbearing ages, including trends in multiple maternities, conceptions terminated by an abortion, and the effects of delayed childbearing on births outside marriage and on the birth order distribution of births within marriage.

Adult↗
PubMed1994

Effort and achievement in national family planning programmes.

New data show that national family planning programmes have made impressive progress in the last 25 years. Fertility rates have been reduced dramatically, but during the current decade even greater achievements will be called for.

Family Planning Services↗
PubMed1994

Postnatal maturation of baroreflex heart rate control in neonatal swine.

OBJECTIVE: Despite extensive knowledge about basic baroreceptor function, there continues to be controversy as to whether there is postnatal maturation of the cardiovascular baroreflex. DESIGN/ANIMALS: Acutely studied postnatal developmental changes in baroreflex sensitivity with a neonatal porcine model in 28 chloralose-anesthetized piglets from birth to six weeks of age. INTERVENTIONS: Steady-state heart rate versus blood pressure response curves were generated by altering blood pressure with increasing doses of phenylephrine or nitroprusside. Data were fitted to the Hill equation for sigmoidal curves, and the maximum heart rate, maximum slope (sensitivity) and blood pressure at 50% maximal heart rate (P50) were calculated. MAIN RESULTS: Baroreflex sensitivity was found to increase from birth to six weeks of age (P < 0.0001), with the most rapid changes occurring after two weeks of age. Increasing age was accompanied by shift of the baroresponse curve to an increased range of heart rate changes at higher blood pressures. Maximal heart rates did not differ with advancing postnatal age. CONCLUSIONS: Swine baroreflex sensitivity increases from birth to six weeks of age, with higher blood pressures causing greater bradycardia in older piglets. These findings are consistent with postnatal maturation of the cardiovascular autonomic nervous system.

Age Factors↗