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.