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96 Perspectives on Sexual and Reproductive Health FYI WORLD POPULATION FUN FACTS In June 1999, the world popula- tion reached six billion—3.5 times its size at the beginning of the 20th century and twice its size in 1960—according to a re- port from the Census Bureau. 1 The climb from five billion to six billion took a mere 12 years; by comparison, it took 118 years for the population to inch its way from one billion to two bil- lion and 37 years for the next billion to be added. In 2002, the annual rate of population growth was 1.2%, the equiva- lent of 200,000 people a day, or 74 million a year; at that rate, roughly the number of people living in western Europe in 2002 will be added to the world population over five years. Dra- matic as all of this may sound, growth is slowing: The number of people added in one year peaked at 87 million in 1989–1990, and the annual growth rate was 2.2% in the early 1960s. Analysts attribute the slowdown to fertility de- clines: Worldwide, women in 1990 had a lifetime average of 3.3 children; the figure was 2.6 in 2002 and is likely to drop below replacement level by 2050. The Census report takes a detailed look at these and other population-related trends and their projected impacts for the first half of this century. 1. U.S. Census Bureau, Global popula- tion at a glance: 2002 and beyond, International Brief, Washington, DC: U.S. Census Bureau, 2004. PROGRAM WORKS; BOOSTER DOESN’T Four years after students in 10 North Carolina public schools participated in a program to re- duce dating violence, they were significantly less likely than their peers who had not received the intervention to report involve- ment in such violence. 1 The Safe Dates program included a the- atrical production staged by stu- dents, 10 educational sessions and a poster contest, and was implemented among eighth graders in five randomly select- ed schools in 1994–1995. Three years later, half of participants received a booster—a mailed newsletter and worksheets, fol- lowed by a phone call from a health educator—to reinforce the program’s messages. According to the teenagers’ own reports four years after the intervention, Safe Date participants had per- petrated significantly less physi- cal, serious physical and sexual abuse within a dating relation- ship than students whose schools had not provided the program (betas, –0.1 to –1.1); they also were less likely to have been victims of sexual or serious physical violence (–0.2 and –0.5, respectively). Program effects were the same for white and nonwhite teenagers, and for males and females, but they var- ied somewhat by whether ado- lescents had previously experi- enced dating violence. However, students who received the boost- er did not report better out- comes than those who received only the original intervention. 1. Foshee VA et al., Assessing the long- term effects of the Safe Dates program and a booster in preventing and reduc- ing adolescent dating violence victim- ization and perpetration, American Journal of Public Health, 2004, 94(4): 619–624. DOES TRUE LOVE WAIT? Fourteen percent of participants in the National Longitudinal Study of Adolescent Health who had taken a virginity pledge had a nonmarital birth; the propor- tion was twice as high among their counterparts who had not taken a pledge. 1 In an analysis by the Heritage Foundation, the difference could not be attrib- uted to teenagers’ family struc- ture or income, religiosity, self- esteem, school performance or race. When these factors were controlled for, pledgers had 40% lower odds of giving birth out of wedlock than non- pledgers. According to the ana- PILL-STROKE LINK: CASE NOT CLOSED Although 30 years of research have pointed to a link between birth control pill use and the risk of stroke, the association is ”tenuous at best and perhaps nonexistent,” according to a meta-analysis includ- ing 36 studies. 1 Overall, the pooled data showed that pill users had nearly twice nonusers’ stroke risk (odds ratio, 1.9). The association was significant in case-control studies (2.1), for stroke caused by blood clots (2.7) and for current pill users (2.0). However, the data suggest a negative association in cohort studies, show no association for stroke caused by bleeding in the brain or for stroke-related deaths, and indicate no elevation in risk for ever-users. Increases in risk were similar regardless of estrogen dose (1.8 for high- and low- dose pills) or type of progestin (2.4–2.9). Women’s risk factors were key to the relationship: Increases in risk were more marked for pill users who were 35 or older (2.3), smoked (3.5) or had high blood pressure (9.8) than for users without these risk factors (1.3–2.1). The analysts contend that the inconsistencies in the data, the low ab- solute values of the odds ratios and “severe methodological limita- tions” (which they outline in their report) cast doubt on the associa- tion between pill use and stroke risk, particularly in young women who do not smoke or have high blood pressure. 1. Chan W-S et al., Risk of stroke in women exposed to low-dose oral contracep- tives: a critical evaluation of the evidence, Archives of Internal Medicine, 2004, 164(7):741–747. FYI is compiled and written by Dore Hollander, executive editor of Perspectives on Sexual and Reproductive Health.

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Page 1: WORLD POPULATION FUN FACTS

96 Perspectives on Sexual and Reproductive Health

F Y I

WORLD POPULATION FUN FACTSIn June 1999, the world popula-tion reached six billion—3.5times its size at the beginning ofthe 20th century and twice itssize in 1960—according to a re-port from the Census Bureau.1

The climb from five billion to sixbillion took a mere 12 years; bycomparison, it took 118 yearsfor the population to inch itsway from one billion to two bil-lion and 37 years for the nextbillion to be added. In 2002, theannual rate of populationgrowth was 1.2%, the equiva-lent of 200,000 people a day, or74 million a year; at that rate,roughly the number of peopleliving in western Europe in2002 will be added to the worldpopulation over five years. Dra-matic as all of this may sound,growth is slowing: The numberof people added in one yearpeaked at 87 million in1989–1990, and the annualgrowth rate was 2.2% in theearly 1960s. Analysts attributethe slowdown to fertility de-clines: Worldwide, women in

1990 had a lifetime average of3.3 children; the figure was 2.6in 2002 and is likely to dropbelow replacement level by2050. The Census report takes adetailed look at these and otherpopulation-related trends andtheir projected impacts for thefirst half of this century.

1. U.S. Census Bureau, Global popula-tion at a glance: 2002 and beyond,International Brief, Washington, DC:U.S. Census Bureau, 2004.

PROGRAM WORKS;BOOSTER DOESN’TFour years after students in 10North Carolina public schoolsparticipated in a program to re-duce dating violence, they weresignificantly less likely than theirpeers who had not received theintervention to report involve-ment in such violence.1 The SafeDates program included a the-atrical production staged by stu-dents, 10 educational sessionsand a poster contest, and wasimplemented among eighthgraders in five randomly select-

ed schools in 1994–1995. Threeyears later, half of participantsreceived a booster—a mailednewsletter and worksheets, fol-lowed by a phone call from ahealth educator—to reinforce theprogram’s messages. Accordingto the teenagers’ own reportsfour years after the intervention,Safe Date participants had per-petrated significantly less physi-cal, serious physical and sexualabuse within a dating relation-ship than students whoseschools had not provided theprogram (betas, –0.1 to –1.1);they also were less likely to havebeen victims of sexual or seriousphysical violence (–0.2 and –0.5,respectively). Program effectswere the same for white andnonwhite teenagers, and formales and females, but they var-ied somewhat by whether ado-lescents had previously experi-enced dating violence. However,students who received the boost-er did not report better out-comes than those who receivedonly the original intervention.

1. Foshee VA et al., Assessing the long-term effects of the Safe Dates programand a booster in preventing and reduc-ing adolescent dating violence victim-ization and perpetration, AmericanJournal of Public Health, 2004, 94(4):619–624.

DOES TRUE LOVE WAIT?Fourteen percent of participantsin the National LongitudinalStudy of Adolescent Health whohad taken a virginity pledge hada nonmarital birth; the propor-tion was twice as high amongtheir counterparts who had nottaken a pledge.1 In an analysisby the Heritage Foundation, thedifference could not be attrib-uted to teenagers’ family struc-ture or income, religiosity, self-esteem, school performance orrace. When these factors werecontrolled for, pledgers had40% lower odds of giving birthout of wedlock than non-pledgers. According to the ana-

PILL-STROKE LINK: CASE NOT CLOSEDAlthough 30 years of research have pointed to a link between birthcontrol pill use and the risk of stroke, the association is ”tenuous atbest and perhaps nonexistent,” according to a meta-analysis includ-ing 36 studies.1 Overall, the pooled data showed that pill users hadnearly twice nonusers’ stroke risk (odds ratio, 1.9). The associationwas significant in case-control studies (2.1), for stroke caused byblood clots (2.7) and for current pill users (2.0). However, the datasuggest a negative association in cohort studies, show no associationfor stroke caused by bleeding in the brain or for stroke-relateddeaths, and indicate no elevation in risk for ever-users. Increases inrisk were similar regardless of estrogen dose (1.8 for high- and low-dose pills) or type of progestin (2.4–2.9). Women’s risk factors werekey to the relationship: Increases in risk were more marked for pillusers who were 35 or older (2.3), smoked (3.5) or had high bloodpressure (9.8) than for users without these risk factors (1.3–2.1). Theanalysts contend that the inconsistencies in the data, the low ab-solute values of the odds ratios and “severe methodological limita-tions” (which they outline in their report) cast doubt on the associa-tion between pill use and stroke risk, particularly in young womenwho do not smoke or have high blood pressure.

1. Chan W-S et al., Risk of stroke in women exposed to low-dose oral contracep-tives: a critical evaluation of the evidence, Archives of Internal Medicine, 2004,164(7):741–747.

FYI is compiled and written byDore Hollander, executive editor of

Perspectives on Sexual andReproductive Health.