SOURCES
OF DATA
Births
The chapter on natality encompasses births to New Jersey residents
during the calendar year 1998. The birth certificate is the source
document for data included in the analysis. New Jersey law requires
that the attending physician, midwife, or person acting as midwife
file a certificate of birth with the Local Registrar within five days
of a birth within the state. Statistics on births to New Jersey residents
which occurred in other states are also included in this report. The
inclusion of these data is made possible through the auspices of the
Vital Statistics Cooperative Program, which encourages the exchange
of information on vital events between the states of occurrence and
residence.
In
January of 1996, the New Jersey Department of Health
began a pilot test of its electronic birth certificate (EBC) in four
maternity hospitals in the state. Upon successful completion of this
test, the EBC was systematically installed in other New Jersey birthing
facilities over the next two years. By the end of 1998, all New Jersey
birthing facilities were reporting births to the State through the
EBC system. Future reports in this series will benefit from the improved
quality and timeliness of the data afforded by the EBC, as well as
the enhanced array of perinatal data provided through this system.
The
format of the birth certificate was revised and expanded in 1989.
The position of items on the revised birth certificate led to considerable
confusion between the reporting of a mother's mailing address and
her residence address. In 1998, the Center for Health Statistics completed
a multi-year project involving the application of address standardization
software to convert mailing-label type information so that birth records
could be accurately assigned to geographic areas. With the resolution
of this problem, it is once again possible to display data at the
municipality level. Additionally, births to residents of military
bases and state institutions are now attributed to the municipality
and county where the base or institution is located.
Deaths
The mortality information contained in this report covers deaths of
New Jersey residents during the 1998 calendar year. The report's source
document is the death certificate. New Jersey law requires the prompt
filing of a death certificate by the proper authority, such as hospital
personnel, physicians, medical examiners, and funeral directors, in
the event of a death occurring in the state. These certificates are
submitted to the office of the State Registrar, where they are recorded
and filed permanently. Statistics on deaths of New Jersey residents
which occurred in other states are obtained through participation
in the national Vital Statistics Cooperative Program. Unless otherwise
noted, the data presented in this report are for New Jersey residents.
All
of the causes of deaths included in this report are underlying causes,
and were coded by Bureau of Vital Statistics staff in accordance with
the International Classification of Diseases, Ninth Revision,
adapted for use in the United States. Additional causes of death listed
on the certificates, including the immediate and intermediate causes,
are not considered in the analysis. The inclusion of all listed causes
of death (multiple causes of death) could lead to somewhat different
results.
Infant
Deaths
For the first time in this report series, infant mortality data are
presented from the linked infant death-birth match file which has
death certificates for infants matched with their birth certificates.
This file allows analysis of maternal characteristics and newborn
health information that is not on the death certificate.
It
is important to note that in previous reports in this series, when
infant mortality was reported by race, it was the race of the child
as reported on the death certificate. Beginning with this report,
the race of the mother on the birth certificate will be used. The
race and ethnicity of an infant are not reported on the birth certificate
and are classified for statistical purposes as the race and ethnicity
of the mother. By analyzing infant deaths based on the mother's race
and ethnicity, the data will be comparable with the birth data used
for denominators in calculating infant mortality rates. This also
allows the analysis of infant deaths by Hispanic ethnicity which was
not done in the past due to poor reporting on the death certificate.
Fetal
Deaths
Fetal deaths occurring after the completion of 20 or more weeks of
gestation are required to be reported to the State Registrar by New
Jersey law. Induced abortions of 20 weeks or more gestation are encompassed
by this requirement, but are not included in the fetal death count.
Fetal death figures presented in this report, therefore, include only
spontaneous abortions beyond 19 weeks of gestation. Fetal deaths of
unknown or unstated gestational age are also included. Only fetal
deaths occurring to females who were New Jersey residents are included.
Births, Deaths, and Fetal Deaths
The birth, death, and fetal death data presented in this report were
generated from data files available at the time of preparation of
the respective chapters. Any data pertaining to a vital event for
which a certificate was filed after that time or relating to corrections
or revisions made since the data were processed for this report are
not included. Birth and death computer files are periodically updated
by Bureau of Vital Statistics and Center for Health Statistics staff
based on correction reports received from local registrars and from
quarterly data quality control analyses conducted by the Center for
Health Statistics. This report incorporates data from the most recently
updated files. Thus, 1998 data presented in future reports of vital
events may differ slightly from numbers presented in this report.
Marriages
and Divorces
Information on marriages in this report was obtained from marriage
certificates issued in New Jersey. Marriage certificates are filed
with the State Registrar. Divorce and annulment statistics were provided
by the New Jersey Superior Court, Chancery Division. Marriages are
recorded by the place of issuance of the certificate and divorces
and annulments are recorded by place of judgment. Since no mechanism
for interstate exchange of resident marriage and divorce data exists,
marriages, divorces and annulments of New Jersey residents which occur
outside of the state are not included in this report, while marriages
and divorces of out-of-state residents occurring in New Jersey are
included.
Communicable
Diseases
The chapter is derived from data on cases of reportable diseases submitted
to designated programs of the New Jersey Department of Health responsible for their collection and maintenance.
The New Jersey Sanitary Code and the New Jersey Administrative Code
8:57 require providing notification to the Department of Health of cases of selected communicable diseases. AIDS and
AIDS-Related Complex (ARC) were added to the list of legally reportable
diseases on October 6, 1986, under State Regulation 8:57-1.14. Effective
May 21, 1990, State Regulation 8:57-2.1 was amended to omit ARC as
a reportable condition, and to mandate anonymous reporting of HIV
infections. In October, 1991, the regulations were again amended to
mandate named reporting of HIV infections by providers and in April,
1992 revised to mandate laboratory reporting of HIV infections with
identifiers.
AIDS
and cases of HIV infection are reported to the HIV/AIDS Surveillance
Program in the AIDS Epidemiological Services Unit within the Division
of AIDS Prevention and Control. The Tuberculosis Control Program collects
information on tuberculosis cases occurring in New Jersey through
its monitoring and surveillance activities. Cases of syphilis and
gonorrhea are reported to the Sexually Transmitted Disease Control
Program. Data on selected vaccine-preventable childhood diseases are
reported to the Vaccine Preventable Program and data on all other
communicable diseases are reported to the Infectious and Zoonotic
Program. These programs are coordinated by the Communicable Disease
Service within the Division of Epidemiology, Environmental, & Occupational
Health.
Health
Status
Health objectives tracked in this report are a subset of the objectives
presented in Healthy New Jersey 2000. In this report, only
those based on vital statistics, communicable disease, and Behavioral
Risk Factor Surveillance System data are included. The New Jersey
Behavioral Risk Factor Surveillance System (BRFSS) is part of the
national Behavioral Risk Factor Surveillance System, an ongoing telephone
survey of adults aged 18 years and over. This survey is designed to
monitor modifiable risk factors for chronic diseases and other leading
causes of morbidity and death. The New Jersey Department of Health has been participating in the BRFSS since 1991,
collecting approximately 125 interviews per month through 1995 and
nearly double that number since 1996.
Population
Population figures for 1998 which are presented in this report and
used to calculate various rates are estimates developed by the U.
S. Bureau of the Census for the National Cancer Institute. Estimates
were developed for each state and its counties by age, race, Hispanic
ethnicity, and sex categories. These estimates may be revised by the
Census Bureau, as a series of estimates for the decade is developed.
The current set of estimates presented in this report has not been
rounded. However, it should not be presumed that they have the degree
of accuracy which such precise figures might imply.
ALLOCATION
OF DATA BY RESIDENCE OR OCCURRENCE
For
public health planning and policy determination, the most useful population
to study is usually the resident population of an area. In the case
of births, deaths, and fetal deaths, the existence of resident certificate
exchange agreements among the registration areas in the country permits
analysis of resident birth and death statistics. Unless otherwise
noted, the data presented for births, deaths, and fetal deaths represent
vital events of the resident population. Morbidity data relate to
New Jersey residents; reports of cases of communicable diseases diagnosed
in New Jersey residents in other states are transmitted to the New
Jersey Department of Health. Marriage and divorce
statistics in this report represent vital events which occurred in
New Jersey, regardless of the state of residence of the individuals
involved.
Allocation
of vital events by place of residence within the state is sometimes
difficult because classification depends on the statement of the usual
place of residence provided by the informant at the time the certificate
is completed. For a variety of reasons, the information given may
be incorrectly recorded. A common source of error is the confusion
of mailing address with residence address. A major project to correctly
allocate New Jersey births by municipality of mother's residence has
been completed. As of the 1998 report, selected birth data will be
presented for all municipalities with over 35,000 residents. The degree
to which incorrect information on municipality of residence has been
recorded on death certificates is not precisely known, but this issue
is generally a problem only for certain minor civil divisions. Therefore,
death data are only presented for municipalities with over 35,000
residents which are known to have a relatively low level of uncertainty
in allocation of municipality.
QUALITY
OF DATA
The
reporting of births and deaths is considered to be essentially complete.
According to the National Center for Health Statistics (NCHS), more
than 99 percent of births and deaths are registered. Reporting of
fetal deaths is believed to be somewhat less complete. For later periods
of gestation, however, fetal death reporting is thought to be more
complete (NCHS, 1994). The completeness of reporting by residence
is dependent on the effective functioning of the interstate data exchange
program for certificates which is fostered and encouraged by NCHS.
Research has shown that there is some degree of slippage in receiving
information on all births and deaths of New Jersey residents occurring
in other states. However, the number of missing events is thought
to be small, relative to the overall number of events.
The
quality of the birth, death, and fetal death data included in this
report is a function of the accuracy and completeness of the information
recorded on the respective certificates and of the quality control
procedures employed in the coding and keying processes. A query program
in which the individual(s) responsible for completing the certificate
is questioned about missing or conflicting information is carried
out by staff of the Bureau of Vital Statistics of the New Jersey Department of Health. This process is augmented by the data
quality control analyses performed by the Center for Health Statistics
using all of the NCHS edit criteria.
In
order to participate in the national Vital Statistics Cooperative
Program, states had to achieve an error rate of two percent or less
on each certificate item for three consecutive months. The error rates
relate to both coding and data entry errors. New Jersey has met the
error tolerance requirements for the cooperative program. After satisfying
initial requirements, a monthly sample of records is used to determine
that the error rate on each birth certificate item is approximately
four percent or less and is no more than two percent for each death
certificate item other than the medical cause-of-death information.
Due to the complexity of the coding system, cause-of-death coding
has a five percent error tolerance level set by NCHS. Multiple cause-of-death
coding of New Jersey death records is performed by NCHS staff.
RACE
AND ETHNICITY CLASSIFICATION
A race
group (White, Black, American Indian/Alaska Native, Chinese, Japanese,
Hawaiian, Filipino, Asian Indian, Korean, Samoan, Vietnamese, Guamian,
other Asian/Pacific Islander, other race, and an unknown race category)
and an ethnicity (Non-Hispanic, Mexican, Puerto Rican, Cuban, Central
or South American, other Hispanic, and an unknown ethnicity category)
are reported for each individual for whom a vital record is filed.
The race and ethnicity of an infant are not reported on the birth
certificate and are classified for statistical purposes as the race
and ethnicity of the mother.
Race/ethnicity
designations used in the natality chapter of this report are white
(non-Hispanic), black (non-Hispanic), Hispanic, Asian/Pacific Islander
(non-Hispanic), and other (non-Hispanic) races. The Hispanic category
includes persons of Mexican, Puerto Rican, Cuban, Central/South American,
or other Hispanic ethnicity, regardless of race. The Asian/Pacific
Islander (non-Hispanic) category includes persons of Chinese, Japanese,
Hawaiian, Filipino, Asian Indian, Korean, Samoan, Vietnamese, Guamian,
and other Asian and Pacific Islander descent who were not reported
as Hispanic. The other (non-Hispanic) race category includes all race
groups other than white, black, and Asian/Pacific Islander who were
not reported as Hispanic.
Race
and ethnicity classifications are based on self-reports, or in the
case of death records, on reports from respondents, usually a family
member, or from persons responsible for preparing the death certificates.
Race and ethnicity reporting on birth certificates has been found
to be virtually complete, therefore birth data for Asian/Pacific Islanders
and Hispanics are presented in the natality chapter. However, race
reporting for races other than white and black and reporting of Hispanic
ethnicity on death certificates is incomplete; therefore, data presented
in the mortality chapter are only given for white and black races,
regardless of ethnicity. Persons who are identified as Hispanic have
been included in the analysis of mortality data by race based on the
race reported on the decedent's death certificate. Asians and Pacific
Islanders are included in the other race category.
DEFINITIONS
Natality
Abnormal Conditions of the Newborn (Ventura, et al.,
2000):
Birth Injury: impairment of the infant's body function or structure
due to adverse influences which occurred at birth.
Hyaline Membrane Disease/RDS: a disorder primarily of prematurity,
manifested clinically by respiratory distress and pathologically by
pulmonary hyaline membranes and incomplete expansion of the lungs
at birth.
Meconium Aspiration Syndrome: aspiration of meconium by the
fetus or newborn, affecting the lower respiratory system.
Assisted Ventilation: a mechanical method of assisting respiration
for newborns with respiratory failure.
Apgar
Score: a summary measure of an infant's clinical condition based
on heart rate, respiratory effort, muscle tone, reflex irritability,
and color taken at one and five minutes after delivery. Each of the
factors is given a score of 0, 1, or 2; the sum of these five values
is the Apgar score which can range from 0 to 10. A score of 10 is
optimal and a low score (usually considered to be less than 7) is
considered an indication of potential health problems and raises concerns
about the subsequent health and survival of the infant.
Birth
Weight: the first weight of the fetus or newborn obtained after
delivery. Birth weight is recorded in grams.
Complications
of Labor and/or Delivery (Ventura, et al., 2000):
Febrile: a fever greater than 100 degrees F or 38 C occurring
during labor and/or delivery.
Moderate or Heavy Meconium: meconium consists of undigested
debris from swallowed amniotic fluid, various products of secretion,
excretion, and shedding by the gastrointestinal tract; moderate to
heavy amounts of meconium in the amniotic fluid noted during labor
and/or delivery.
Premature Rupture of Membranes (More than 12 Hours): rupture
of the membranes at any time during pregnancy and more than 12 hours
before the onset of labor.
Abruptio Placenta: premature separation of a normally implanted
placenta from the uterus.
Placenta Previa: implantation of the placenta over or near
the internal opening of the cervix.
Other Excessive Bleeding: the loss of a significant amount of blood
from conditions other than abruptio placenta or placenta previa. An
EBC software cross-edit does not allow this complication to be selected
unless blood loss greater than or equal to 750 cc for vaginal deliveries
and 1,200 cc for cesarean deliveries is entered.
Precipitous Labor (Less than 3 Hours): extremely rapid labor
and delivery lasting less then 3 hours.
Prolonged Labor (More than 20 Hours): abnormally slow progress
of labor lasting more than 20 hours.
Dysfunctional Labor: failure to progress in a normal pattern
of labor.
Breech/Malpresentation: at birth, the presentation of the fetal
buttocks rather than the head, or other malpresentation.
Cephalopelvic Disproportion: the relationship of the size,
presentation, and position of the fetal head to the maternal pelvis
which prevents dilation of the cervix and/or descent of the fetal
head.
Cord Prolapse: premature expulsion of the umbilical cord in
labor before the fetus is delivered.
Fetal Distress: signs indicating fetal hypoxia (deficiency
in amount of oxygen reaching fetal tissues).
Congenital
Anomalies of the Child (Ventura, et al., 2000):
Central Nervous System Anomaly: includes anencephalus, spina
bifida/meningocele, hydrocephalus, microcephalus, or other anomaly
of the brain, spinal cord, or nervous system.
Heart Malformation: congenital anomaly of the heart.
Other Circulatory/Respiratory Anomaly: other specified anomalies
of the circulatory or respiratory systems.
Gastrointestinal Anomaly: includes rectal atresia/stenosis,
tracheo-esophageal fistula/esophageal atresia, omphalocele/gastroschisis,
or other anomaly of the gastrointestinal system.
Urogenital Anomaly: malformed genitalia, renal agenesis, or
other anomaly of the organs concerned in the production and excretion
of urine, together with organs of reproduction.
Cleft Lip/Palate: cleft lip is a fissure or elongated opening
of the lip; cleft palate is a fissure in the roof of the mouth.
Polydactyly/Syndactyly/Adactyly: polydactyly is the presence of more
than five digits on either hands and/or feet; syndactyly is having
fused or webbed fingers and/or toes; adactyly is the absence of fingers
and/or toes.
Club Foot: deformities of the foot, which is twisted out of
shape or position.
Other Musculoskeletal/Integumental Anomaly: includes diaphragmatic
hernia or other anomaly of the muscles, skeleton, or skin.
Down's Syndrome: the most common chromosomal defect with most
cases resulting from an extra chromosome.
Other Chromosomal Anomaly: any other chromosomal aberration.
Live
Birth: the complete expulsion or extraction from its mother of
a product of conception, irrespective of the duration of pregnancy,
which, after such separation, breathes or shows any evidence of life,
such as beating of the heart, pulsation of the umbilical cord, or
definite movement of voluntary muscles.
Low
Birth Weight: birth weight of less than 2,500 grams or approximately
5 pounds, 8 ounces. Prior to 1989, New Jersey defined low birth weight
as 2,500 grams or less.
Marital
Status: the marital status of the mother for statistical purposes
is determined for data years after 1988 by the response to the birth
certificate item, "Mother married? (At birth, conception, or any time
between)".
Medical
Risk Factors for This Pregnancy (Ventura, et al., 2000):
Anemia: hemoglobin level of less than 10.0 g/dL during pregnancy
or a hematocrit of less than 30 percent during pregnancy.
Cardiac Disease: disease of the heart.
Acute or Chronic Lung Disease: disease of the lungs during
pregnancy.
Diabetes: metabolic disorder characterized by excessive discharge
of urine and persistent thirst; includes juvenile onset, adult onset,
and gestational diabetes during pregnancy.
Genital Herpes: infection of the skin of the genital area by
herpes simplex virus.
Hydramnios/Oligohydramnios: any noticeable excess (hydramnios)
or lack (oligohydramnios) of amniotic fluid.
Hemoglobinopathy: a blood disorder caused by alteration in
the genetically determined molecular structure of hemoglobin (example:
sickle cell anemia).
Chronic Hypertension: blood pressure persistently greater than
140/90, diagnosed prior to onset of pregnancy or before the 20th week
of gestation.
Pregnancy-Associated Hypertension: an increase in blood pressure
of at least 30mm Hg systolic or 15mm Hg diastolic on two measurements
taken 6 hours apart after the 20th week of gestation.
Eclampsia: the occurrence of convulsions and/or coma unrelated
to other cerebral conditions in women with signs and symptoms of preeclampsia.
Incompetent Cervix: characterized by painless dilation of the
cervix in the second trimester or early in the third trimester of
pregnancy, with premature expulsion of membranes through the cervix
and ballooning of the membranes into the vagina, followed by rupture
of the membranes and subsequent expulsion of the fetus.
Previous Infant 4,000+ grams: the birth weight of a previous
live-born child was over 4,000 grams (8 pounds, 14 ounces).
Previous Preterm or Small-for-Gestational Age Infant: previous
birth of an infant prior to term (before 37 completed weeks of gestation)
or of an infant weighing less than the tenth percentile for gestational
age using a standard weight-for-age chart.
Renal Disease: kidney disease.
Rh Sensitization: the process or state of becoming sensitized
to the Rh factor as when an Rh-negative woman is pregnant with an
Rh-positive fetus.
Uterine Bleeding: any clinically significant bleeding during
the pregnancy taking into consideration the stage of pregnancy; any
second or third trimester bleeding of the uterus prior to the onset
of labor.
Multiple
Births: individual births in twin, triplet, quadruplet, and higher
order multiple deliveries.
Obstetric
Procedures (Ventura, et al., 2000):
Amniocentesis: surgical transabdominal perforation of the uterus
to obtain amniotic fluid to be used in the detection of genetic disorders,
fetal abnormalities, and fetal lung maturity.
Electronic Fetal Monitoring: monitoring with external devices
applied to the maternal abdomen or with internal devices with an electrode
attached to the fetal scalp and a catheter through the cervix into
the uterus, to detect and record fetal heart tones and uterine contractions.
Induction of Labor: the initiation of uterine contractions
before the spontaneous onset of labor by medical and/or surgical means
for the purpose of delivery.
Stimulation of Labor: augmentation of previously established
labor by use of oxytocin.
Tocolysis: use of medications to inhibit preterm uterine contractions
to extend the length of pregnancy and, therefore, avoid a preterm
birth.
Ultrasound: visualization of the fetus and the placenta by
means of sound waves.
Plurality: singleton, twin, triplet, quadruplet, etc.
Previous
Pregnancy Terminations: from the mother's pregnancy history on
the certificate of live birth, a previous spontaneous or induced termination
of pregnancy at any time after conception that did not result in a
live birth.
Teen
Birth: birth to a mother under 20 years of age.
Tobacco,
alcohol, and drug use during pregnancy: use of these substances self-reported
by mother.
Trimester
of Pregnancy: the first trimester includes the first 12 weeks
of pregnancy, the second trimester encompasses the thirteenth through
twenty-fourth weeks and the third trimester is the period after the
twenty-fourth week through delivery.
Very
Low Birth Weight: birth weight of less than 1,500 grams or approximately
3 pounds, 5 ounces.
Mortality
Cause of Death Classification: a system of specification of
the diseases and/or injuries which led to death and the sequential
order of their occurrence. The version of the system in use in 1998
was the International Classification of Diseases, Ninth Revision
(1977), sponsored by the World Health Organization.
Fetal
Death: death prior to the complete expulsion or extraction from
its mother of a product of conception; the fetus shows no signs of
life such as breathing or beating of the heart, pulsation of the umbilical
cord, or definite movement of voluntary muscles. Fetal deaths are
also referred to as stillbirths, miscarriages, or abortions.
Infant Death: death within the first year of life.
Maternal
Death: a death in which the certifying physician has designated
a maternal condition as the underlying cause of death. In the Ninth
Revision of the International Classification of Diseases, (1977),
the World Health Organization defined a maternal death as "the death
of a woman while pregnant or within 42 days of termination of pregnancy,
irrespective of the duration and site of the pregnancy, from any cause
related to or aggravated by the pregnancy or its management but not
from accidental or incidental causes".
Neonatal
Death: death of an infant within the first 27 days of life.
Perinatal
Mortality: for purposes of this report, includes fetal deaths
of 20 or more weeks of gestation and neonatal deaths.
Postneonatal
Mortality: death of an infant from 28 days to one year of life.
Underlying
Cause of Death: the disease or injury which initiated the train
of events leading directly to death or the circumstances of the unintentional
injury or violence which produced the fatal injury. All cause-of-death
data in this report relate to the underlying cause of death coded
from the death certificate.
Years
of Potential Life Lost (YPLL): a measure of the number of years
of life not lived by each individual who died before reaching a predetermined
age. For purposes of this report, the predetermined age is 65. This
measure weights deaths at younger ages more heavily than deaths at
older ages; the younger the age at death, the greater the number of
years of potential life lost. The YPLL for a population is computed
as the sum of all the individual YPLL for individuals who died during
a specific time period.
Communicable
Diseases
Stages of Syphilis (Larsen, et. al., 1990):
Primary Syphilis: begins within approximately 30 hours after
infection; a primary chancre usually forms within two through six
weeks of infection. Both treponemal and nontreponemal antibodies appear
one through four weeks after the lesion has formed. Even without treatment,
the lesion usually resolves within two months.
Secondary Syphilis: occurs within six weeks of healing of the
primary lesion. Disseminated lesions appear that are attributable
to systemic infection. Virtually every organ and tissue of the body
are affected. Whether treated or untreated, the lesions of secondary
syphilis usually resolve within 2 through 10 weeks.
Latent Syphilis: this stage represents a conversion from an
acute to a chronic infection. After the first year, the host's immune
response suppresses the infection to the point where lesions are not
clinically apparent. A patient with reactive nontreponemal or treponemal
tests in the absence of clinical symptoms is said to have latent syphilis.
A patient is categorized as having early latent syphilis if the serologic
tests of that patient have been nonreactive within the preceding year
or if symptoms suggestive of primary or secondary syphilis were present
during that time. Other patients are considered to have late latent
syphilis and should be evaluated for potential asymptomatic neurosyphilis.
Verified
Case of Tuberculosis: is also referred to as a new active case
of tuberculosis. These cases are characterized by (1) any bacteriological
confirmation of the presence of Mycobacterium tuberculosis or (2)
in the absence of bacteriological confirmation, for a diagnosis of
active pulmonary tuberculosis the patient must present a positive
purified protein derivative (PPD), or must exhibit a positive chest
x-ray, or in the case of children, must be epidemiologically linked
to another active case of tuberculosis. In the case of extrapulmonary
tuberculosis, the patient must show signs of clinical improvement
while taking tuberculosis medication (K. Shilkret, personal communication,
1992).
All
Tables in the Report
Not Stated: an inclusive term used to represent data which
are missing, unknown, not available, or not classifiable.
RATES
AND RATIOS
The
presentation of vital statistics in the form of rates and ratios facilitates
comparisons between political subdivisions with populations of different
sizes or between subgroups of a population. Crude rates are calculated
by dividing the number of events of a type that occur to the residents
of an area (e.g., births, deaths) by the resident population of an
area or subgroup. The events are limited to those that occur within
a specific time period, usually a year, and the population is, in
general, the mid-year estimate of the resident population of the area,
although census counts as of April 1 may be used in decennial census
years. Crude rates are expressed in terms of occurrences within a
standard, rounded population, usually 1,000 or 100,000.
While
the denominators for rates consist of the population at risk of the
events included in the numerator (e.g., births, deaths), ratios are
designed to indicate the relationship between two counts in which
the denominator population is not at risk of the events included in
the numerator. An example of a ratio contained in this report is the
maternal mortality ratio in which the number of deaths due to maternal
causes forms the numerator and the number of live births provides
the denominator.
In
order to compare natality and mortality experience among various ages
and races or between the sexes, rates may be computed for subgroups
of the population. These are referred to as age-, race-, or sex-specific
rates and are calculated by dividing the relevant events within a
subgroup by the population in the subgroup. Death rates from specific
causes may also be calculated, with the numerator consisting of the
deaths from the particular cause in an area and the denominator comprised
of the population at risk of the disease or condition.
The
numbers of births and deaths in an area are directly related to the
demographic characteristics of the area's population. In comparing
rates over time or among geographic areas, it is helpful to eliminate
the effects of the differences in the populations' demographic characteristics
on the comparison. This can be accomplished through adjustments of
the rates for the particular characteristics of interest. Since age
is the variable that has the greatest effect on the magnitude of rates
(Shryock, Siegel, et al., 1976), the most common type of adjustment
of rates is for age. Direct adjustment of vital statistics rates involves
application of existing rates (age-, race-, or sex-specific) to a
standard population to arrive at the theoretical number of events
that would occur in the standard population, at the rates prevailing
in the actual population. These events are then divided by the total
number of persons in the standard population to arrive at an adjusted
rate. Adjusted rates are index numbers and cannot be compared to crude
or other actual rates. The use of adjusted rates is limited to comparison
with other adjusted rates, based on the same standard population.
The standard population used in this report is the United States 1940
standard million, derived from the counts of the 1940 decennial census.
The
definition of rates and ratios used in this report follows. It should
be noted that alternative forms exist for some of these statistics.
Some other states and the federal government may employ different
formulae for the computation of selected rates, in particular, the
perinatal and fetal death rates.
Crude
Birth Rate: the number of resident live births per 1,000 population.
General
Fertility Rate: the number of resident live births per 1,000 females
aged 15-44 years.
Total
Fertility Rate: age-specific birth rates of women in five-year
age groups multiplied by five and summed to form a total for all ages.
This rate indicates the number of children a cohort of 1,000 women
would bear if they experienced the existing age-specific birth rates
throughout their childbearing years.
Age-Specific
Birth Rate: the number of resident live births to females in a
specific age group per 1,000 females in the age group.
Crude
Death Rate: the number of resident deaths per 100,000 population.
Age-Adjusted
Death Rate: Direct Method-the elimination of the effect of age
on the crude death rates for purposes of comparison with other rates
by applying actual age-specific rates to a standard population. The
resulting death rate in the standard population is age-adjusted and
can be compared to other death rates age-adjusted to the same standard
population.
Cause-Specific
Death Rate: the number of resident deaths from a specific cause
per 100,000 population.
Infant
Death Rate: the number of resident deaths under one year of age
per 1,000 population.
Infant
Mortality Rate: the ratio of the number of deaths to children
less than one year of age in a given year per 1,000 births in the
same year.
Neonatal
Death Rate: the number of resident infant deaths within the first
27 days of life per 1,000 live births.
Postneonatal
Death Rate: the number of resident infant deaths from 28 days
to one year of life per 1,000 live births.
Perinatal
Death Rate: the number of resident neonatal deaths plus resident
fetal deaths of 20 or more weeks gestation per 1,000 resident live
births plus fetal deaths of 20 or more weeks gestation.
Fetal
Death Rate: the number of resident fetal deaths of 20 or more
weeks gestation per 1,000 resident live births plus fetal deaths of
20 or more weeks of gestation.
Maternal
Mortality Ratio: the number of resident deaths from complications
of pregnancy, childbirth, and the puerperium per 100,000 resident
live births.
Marriage
Rate: the number of marriage certificates issued in an area per
1,000 population.
Divorce
Rate: the number of divorces occurring in an area per 1,000 population.
Caution
should be exercised in the interpretation of rates and ratios based
on small numbers. Chance variations in the number of vital events
occurring in sparsely populated areas can cause rates to fluctuate
widely over time. In accordance with NCHS standards, percentages or
rates based on fewer than 20 cases are considered unreliable for analysis
purposes. Therefore, these percentages and rates are not displayed
and are indicated by ** in the appropriate cell. For purposes of analyzing
vital statistics rates for small areas, calculation of three- or five-year
average rates and other statistical methodologies for analyzing small
numbers may provide more meaningful measures.
CAUSE-OF-DEATH
RANKINGS
The
cause-of-death rankings found in this report are based on distinct
causes of death from the list of 35 cause groups and a residual category
employed in the cause-of-death distributions by race-sex groups and
age and by county in the report. The one exception is that the cause
groups Motor Vehicle Fatalities and Other Unintentional Injuries are
combined into a single category, Unintentional Injuries, for purposes
of ranking leading causes of death. As of the publication of New
Jersey Health Statistics, 1992, a minor change was made in the
grouping of certain infectious and parasitic diseases which transferred
a few ICD-9 codes that had previously been included in the "Residual"
category and to the "Other Infectious and Parasitic Disease" grouping.
This was done to make the groupings more consistent with NCHS' presentation
of mortality data.
The
cause-of-death ranking of infant deaths is based on the NCHS List
of 61 Selected Causes of Infant Death (Murphy, S.L., 2000).
