D., RODRICK WALLACE, PH.D.,. AND ROBERT MOORE, M.P.H.. Epidemiology of Mental Disorders Research Department. New York State Psychiatric Institute.
463
HOUSING CONDITIONS AND THE QUALITY OF CHILDREN AT BIRTH* ELMER L. STRUENING, PH.D., RODRICK WALLACE, PH.D., AND ROBERT MOORE, M.P.H. Epidemiology of Mental Disorders Research Department New York State Psychiatric Institute New York, New York
A NOTHER PAPER IN THIS WORKSHOP, by Wallace and Wallace, exam-
A ines a broad pattern of health status deterioration in New York City populations after 1970. Their studied indices include citywide changes in time of nonwhite infant mortality and, in space, of patterns of low birth weight for the Bronx between 1970 and 1980. They found strong associations between estimates of the widespread "South Bronx" disruption and depopulation of minority neighborhoods and subsequent deterioration in the health status of neighborhood populations. We examine changes in citywide distributions of low birth weight rates for the city's health area populations during the periods 1969-71, 1979-81, and 1985-87, and discuss possible causes and implications of those changes. The 338 health areas of this study are aggregates of census tracts by which birth outcome, morbidity, and mortality data are reported for New York City. Traditionally, under conditions of relatively slow rates of neighborhood change and of continuing relative social stability, cross-sectional studies of New York City, using small areas, have shown dependence of low birth weight rates on housing overcrowding, family income, and rates of divorce and separation. ' Other studies show dependence on fertility structure (maternal age and parity, i.e., number of previous births), neighborhood socioeconomic status, and availability of prenatal services,2 all factors likely to be closely intertwined with overcrowding, income, and community and family stability. Here we extend the analysis, focusing on rapid changes in time and space of patterns of low birth weight rate. In combination with data on the "South Bronx" disruption of minority communities in the city between 1970 and *Presented as part of a Workshop on Housing and Health: Interrelationship and Community Impact held by the Committee on Public Health of the New York Academy of Medicine November 17 and 18, 1989.
Vol. 66, No. 5, September-October 1990
464
OThERS E.L. STRUENING AND OTHERS
464EL. STRUENING
1980, this viewpoint, focused on studying changes in time, provides striking insight not possible in earlier cross-sectional analyses. VARIATES USED FOR HEALTH AREA ANALYSIS
The rate of low birth weight: defined as the number of children born alive and weighing less than 2,501 grams, divided by the total number of children born alive during the time period (singleton births only). Socioeconomic status rank: a composite of income, education, and employment status from the 1970 and 1980 censuses used to rank New York City health areas, using the method reported in Solimano et al.2 Low number indicates higher status rank. Percent black: the number of residents identified by the census as "black" divided by the total number of health area residents. Total housing units: number of occupied housing units- single family homes or individual apartments in multi-unit buildings. Fractional change in housing units: number of occupied housing units for 1980, minus the number for 1970, divided by the number for 1970. Fractional crowded housing units: number of occupied housing units with more than 1.01 persons per room divided by total number of occupied housing units. Table I displays the low birth weight distributions for the 1970, 1980, and 1986 periods, and Table II certain summary statistics. Figures la, b, and c graph those distributions. A Kolmogorov-Smirnov test finds the distributions for 1980 and 1986 highly similar to each other, while both differ considerably from that for 1970 (p < 0.05). While the minimum of all three distributions decreases uniformly in time, the maximum also increases uniformly. Finally, and importantly, examination of Figure 1 shows development of a persistent secondary peak or "shoulder" for the distributions after 1970. This suggests development of a bimodal distribution between 1970 and 1980 which persists through 1986. In Figure 2 and Table III we reclassify the three distributions according to the fraction of the health area population identified as of African-American descent by the 1970 and 1980 census. Health areas are classified according to an "Index," taking the value 0 if the population fraction African-American is less than 0.1, 1 if it is between 0.1 and less than 0.9, and 2 if greater or equal to 0.9. Figure 2a (i.e., 1970) shows a consistent pattern of increasing shift in low birth weight distribution according to the index value, with each distribution clearly defined, consistent with the results of Struening et al. I From Figure 2b Bull. N.Y. Acad. Med.
QUALITY OF CHILDREN
465 465~~~~~~~~~~~~~~~
TABLE I. DISTRIBUTION OF NEW YORK CITY HEALTH AREAS ACCORDING TO PERCENT BABIES BORN AT LESS THAN 2,501 GRAMS
Percent babies born at less than 2,501 grams 2.00- 2.99 3.00- 3.99 4.00- 4.99 5.00- 5.99 6.00- 6.99 7.00- 7.99 8.00- 8.99 9.00- 9.99 10.00-10.99
11.00-11.99 12.00-12.99 13.00-13.99 14.00-14.99 15.00-15.99 16.00-16.99 17.00-17.99 18.00-18.99 19.00-19.99 20.00-20.99 21.00-21.99 22.00-22.99 23.00-23.99 24.00-24.99 Total
Health area frequencies 1970 1980 1986 0 3 6 3 15 16 5 42 57 44 45 42 53 42 37 50 39 30 45 26 27 33 28 30 26 31 24 25 25 26 15 18 14 17 8 10 8 5 7 7 1 3 4 0 3 3 3 1 0 2 3 0 3 0 0 1 1 0 1 0 0 0 0 0 0 0 0 0 1 338 338 338
Cumulative percent 1970 1980 1986 0.0 0.9 1.8 0.9 5.3 6.5 2.4 17.8 23.4 15.4 31.1 35.8 31.1 43.5 46.7 45.9 55.0 55.6 59.2 62.7 63.6 68.9 71.0 72.5 76.6 80.2 79.6 84.0 87.6 87.3 88.5 92.9 91.4 93.5 95.3 94.4 95.9 96.7 96.4 97.9 97.0 97.3 99.1 97.0 98.2 100.0 97.9 98.5 98.5 99.4 99.4 99.4 99.7 99.7 100.0 99.7 99.7 _ 99.7 100.0
TABLE II.
SUMMARY STATISTICS FOR THREE LOW BIRTHWEIGHT VARIABLES Variable LBW 1970 LBW 1980 LBW 1986 Sample size 338 338 338 Average 0.0891479 0.0819893 0.080109 Median 0.0828 0.0751 0.0720951 Mode 0.0711 0.0573 0.0700326 Variance 8.61879E-4 1.19157E-3 1.24118E-3 Standard deviation 0.0293578 0.0345191 0.0352304 Minimum 0.0316 0.0247 0.0206379 Maximum 0.176 0.2151 0.246914 Range 0.1444 0.1904 0.226276
and Table III we see between 1970 and 1980 a general downward shift of the health areas with index value 0 and 1, but a remarkable bifurcation of the distribution in health areas 90% or more African-American, as well as the split-off of two health areas from the distribution with Index value 1. This Vol. 66, No. 5, September-October 1990
466
E.L. STRUENING AND OTHERS
TABLE III. SUMMARY STATISTICS FOR DISTRIBUTIONS 1970 Average Sample size Index value 0.07013 186 0 0.10685 133 1 0.15138 19 2
BY INDEX VALUE
Median 0.06865 0.10560 0.15640
Mode 0.07110 0.10560 0.15240
St. dev. 0.01551 0.02082 0.01848
Minimum 0.03160 0.06380 0.10430
Maximum 0.13280 0.15640 0.17600
Range 0.10120 0.09260 0.07170
Index value 0 1 2
Sample size 155 160 23
1980 Average 0.05659 0.09651 0.15218
Median 0.05370 0.09635 0.13870
Mode 0.05670 0.07250 0.13810
Index value 0
St. dev. 0.01668 0.02293 0.03576
Minimum 0.02470 0.04780 0.10270
Maximum 0.11840 0.17370 0.21510
Range 0.09370 0.12590 0.11240
Median 0.05053 0.09679 0.14072
Mode 0.07003 0.09602 0.13598
Index value 0 1 2
1 2
1986 Index value 0 1 2
Sample size
Average
155 160 23
0.05289 0.09659 0.14889
Maximum Minimum St. dev. 0.11974 0.02064 0.01470 0.18056 0.02878 0.02415 0.24691 0.10579 0.03384 Index: 0 = less than 10% black; 1 = 10 to less than 90% black; 2 = 90 + % black
Index value 0 1 2
Range 0.09910 0.15178 0.14112
pattern is exacerbated for 1986, where the secondary distribution for Index 2 in 1980 shows continuing degradation, while the predominantly white areas show continued improvement between 1980 and 1986; note the sharpening of the low rate peak. Figure 3a maps the location of the 10 high rate health areas of Figure 2b (i.e., 1980) that are "split off" from the distributions for Index values 1 and 2, and, for comparison, Figure 3b maps the health areas that lost or gained African-American population between 1970 and 1980. Bull. N.Y. Acad. Med.
467
0IJALITY OF CHIDREN I OF.PA %ATTVI (HTRN4
TTY
1970
60
50 40 30 -
c as Cr
a,L.
20 -
10-
0I
I
0
I
I
9
I
I
I
a
a
I
9
I I
I
a
a
I
IA
a
a
5
a
I
0
5
I
a
a
I
a
a
5
9
a
I
0.05 0.1 0.15 0.2 0.25 0.3 RATE
Fig. 1. Frequency distributions for New York City Health Areas of rate of low birth weight (no.
