Exposure to Lead and Length of Time Needed to Make Homes Lead-Safe for Young Children

Abstract

Objectives. We determined the length of time needed to make homes lead-safe in a population of children aged 0 to 6 years with blood lead levels (BLLs) of 20 micrograms per deciliter (μg/dL) or greater. Reducing this time would reduce children’s exposure to lead.

Methods. Data came from the Wisconsin Childhood Lead Poisoning Prevention Program’s comprehensive blood lead surveillance system. Analysis was restricted to children whose first BLL test value during 1996–1999 was between 20 and 40 μg/dL and for whom housing intervention data were available (n=382).

Results. The median length of time required to make a home lead-safe was 465 days. Only 18% of children lived in homes that were made lead-safe within 6 months; 45% lived in homes requiring more than 18 months to be lead-safe.

Conclusions. Efforts are needed to reduce the time it takes to make a home lead-safe. Although abatement orders always include time limits, improved compliance with the orders must be enforced. Greater emphasis should be placed on securing lead-safe or lead-free housing for families, thus reducing lead exposure.

Homes are major contributors to elevated blood lead levels (BLLs) in young children, and thus reducing lead levels in homes should reduce BLLs in children. Although elevated BLLs in children have decreased throughout the United States,1^,2 there are still communities in which more than 20% of the children exhibit BLLs of 10 micrograms per deciliter (μg/dL) or greater.2^–4 According to data from the Third National Health and Nutrition Examination Survey, Wisconsin had the third highest prevalence of elevated BLLs in children among the 19 states studied. Statewide, 13% of children tested had BLLs of 10 μg/dL or greater; however, the prevalence in individual counties throughout the state ranged from 3% to 24%.2

The most important factor in controlling lead poisoning is reducing the child’s exposure to lead. Although the number of housing units with lead paint hazards has decreased dramatically since 1990, an estimated 24 million housing units still contain this poisonous material.5 The US Environmental Protection Agency reported in 1995 that 86% of all public housing and 83% of private homes had some lead-based paint.6

Homes built before 1950 create the greatest risk for exposure to lead. In the United States, 27% of homes were built before 1950; however, in the state of Wisconsin, 37% of homes were built before that year.7 It is estimated that 700 000 housing units in Wisconsin contain some lead-based paint hazards, 120000 of which are occupied by children aged younger than 6 years.8

Studies have shown that timely remediation of lead hazards in homes of children with elevated BLLs has a protective effect on increasing lead levels in the blood.9^–11 In fact, low-cost procedures such as enclosing window wells with aluminum and wet-scraping, as well as repainting walls with latex paint, have decreased BLLs as much as 22%.11

Most local health departments are responsible for testing homes when a child has a high BLL. However, each health department follows different rules when dealing with lead-poisoned children and lead hazards. In Wisconsin, once a lead-poisoned child is identified, the local health department has the authority to inspect the dwelling. Abatement orders cannot be written until the inspection is completed, specific hazards are identified, and the needed remediation is identified. Such abatement orders always include time limits.12

The Centers for Disease Control and Prevention recommends that public health officials begin environmental intervention within 10 days of detection of a BLL of 20 μg/dL or greater. Beyond this guideline, little is known about the length of time needed to make homes lead-safe for children with elevated BLLs. Because young children spend much of their time indoors, the home is a significant target for intervention.

METHODS

Data Collection

Data came from the Wisconsin Childhood Lead Poisoning Prevention Program’s comprehensive BLL surveillance system. When a BLL test is given to a child aged younger than 6 years, Wisconsin statutes require the levels to be reported to the prevention program. In cooperation with the laboratories that conduct BLL analysis, the program has maintained a database of all BLL tests, housing interventions, and descriptive characteristics of all children tested throughout Wisconsin.

For our study, analysis was restricted to 382 children whose first BLL test value during 1996–1999 was between 20 and 40 μg/dL and for whom complete housing intervention data were available. We chose the minimum BLL of 20 μg/dL because Wisconsin mandates a lead hazard investigation of residences of children with this BLL.

Data Analysis

The major outcome variable for this study was the length of time needed to make homes lead-safe. Variables investigated that might have affected the outcome included gender, race/ethnicity, age at first BLL of 20 μg/dL or greater, and the value of the first BLL. Because the distribution of ages and times required to make homes lead-safe was skewed, median values, as opposed to means, were reported.

To obtain a description of the variables used, we obtained study variable frequencies and counts of all children. Because of the small percentage of children in race categories other than African American, a dichotomized variable (African American/Other) was created for the analysis.

To evaluate factors that may have been associated with longer time periods for making homes lead-safe, we did a case–control study.

Case children were defined as children whose homes required more than 180 days to be considered lead-safe; control children were defined as children in homes that required 180 days or fewer to be lead-safe.

To examine the individual effects of gender, race/ethnicity, age, and first BLL test value on case or control status, we used simple logistic regression to calculate crude odds ratios and 95% confidence intervals. To evaluate the effect of several predictor variables, we used multivariate logistic regression to calculate adjusted odds ratios and confidence intervals. Variables that were significant in the simple model were maintained in the multivariate model.

RESULTS

Characteristics of Children

The majority (68%) of the children were African American, and 76% of all children had a first BLL test value between 20 and 29 μg/dL. The overall mean first BLL test value for all children was 26 μg/dL (SD= 5.4). Boys were slightly more likely to have a BLL of 30 μg/dL or greater than were girls (26% vs 22%, P= .05). The BLLs differed slightly by race/ethnicity with White children having a mean BLL of 25 μg/dL (SD= 4), African American children having a mean BLL of 26 μg/dL (SD= 5), Hispanic children having a mean BLL of 29 μg/dL (SD= 6), and Asian children having a mean BLL of 27 μg/dL (SD= 6).

The age of the children ranged from 6 months to 6 years. The median age for all children was 27 months. There was no difference in age ranges between boys and girls. However, there was a difference of ages at first BLL test among African American children and children of other races/ethnicities. The median age of African American children at the first BLL test was 24 months, compared with 17 months for White children, 18 months for Hispanic children, and 16 months for Asian children.

Length of Time Required for Homes to Be Considered Lead-Safe

From a child’s first BLL test value of 20 μg/dL or greater, the median length of time needed to make a home lead-safe was 465 days (approximately 1.3 years). The length of time ranged from a minimum of 7 days to a maximum of 1963 days. Over the 4-year period studied, the median time improved from 828 days in 1996 to 347 days in 1999 (Figure 1 ▶).

FIGURE 1—

Median number of days to make homes lead-safe by year of enrollment: Wisconsin, 1996–1999.

Table 1 ▶ shows the characteristics of the children with elevated BLLs by length of time needed to make the home lead-safe. Among all children included in the study, only 18% lived in homes that were made lead-safe within 6 months. Girls were more likely to live in homes that were rendered lead-safe within 6 months than were boys (21% vs 16%). White children were more likely to live in homes that were made lead-safe within 6 months than were African American children (25% vs 13%). Children whose BLLs were 35 μg/dL or greater were more likely to live in homes that were rendered lead-safe within 6 months than were children of other BLLs.

TABLE 1—

Characteristics of Children With Elevated Blood Lead Levels: Wisconsin, 1996–1999

	Length of Time for Home to Be Made Lead-Safe, moa
	Total (n = 382)	0–6, no (%) (n = 70)	7–12, no (%) (n = 86)	13–18, no (%) (n = 52)	≥ 19, no (%)(n = 174)
Gender
Boy	206	33 (16)	44 (21)	26 (13)	103 (50)
Girl	176	37 (21)	42 (24)	26 (15)	71 (40)
Race/ethnicity
White	32	8 (25)	9 (28)	5 (16)	10 (31)
African American	259	33 (13)	58 (22)	37 (14)	131 (51)
Hispanic	14	6 (43)	2 (14)	2 (14)	4 (29)
Asian	14	5 (36)	2 (14)	3 (21)	4 (29)
First BLL test, μg/dL
20–24	183	32 (17)	28 (15)	28 (15)	95 (52)
25–29	107	19 (18)	29 (27)	13 (12)	46 (43)
30–34	56	9 (16)	20 (36)	6 (11)	21 (38)
35–40	36	10 (28)	9 (25)	5 (14)	12 (33)
Age at first BLL test, mo
0–12	65	12 (29)	14 (22)	9 (14)	23 (35)
13–24	150	25 (17)	32 (21)	21 (14)	72 (48)
25–36	80	10 (13)	22 (28)	8 (10)	40 (50)
≥ 37	87	16 (18)	18 (21)	14 (16)	39 (45)
Year of initial BLL test
1996	127	20 (16)	23 (18)	6 (5)	78 (61)
1997	147	19 (13)	40 (27)	24 (16)	64 (44)
1998	59	16 (27)	11 (19)	12 (20)	20 (34)
1999	49	15 (31)	12 (24)	10 (20)	12 (24)

Note. BLL = blood lead level.

^aPercentages may not add to 100% because of missing responses.

Table 1 ▶ shows that the percentage of homes made lead-safe within 6 months improved between 1996 and 1999. In 1996, lead-safety improvements were completed within 6 months in only 16% of homes, whereas in 1999, improvements were completed within 6 months in 31% of homes.

Overall, 46% of children lived in homes that required more than 18 months to be deemed lead-safe. However, the percentage of homes requiring more than 18 months for such improvements decreased dramatically from 1996 to 1999. In 1996, 61% of homes required longer than 18 months to be completed, whereas in 1999, only 24% of homes required more than 18 months for these improvements.

Table 2 ▶ displays the results of the logistic regression used to evaluate factors that may be associated with requiring more than 180 days to make a home lead-safe. African American race was significantly associated with case status.

TABLE 2—

Factors Associated With Requiring Longer Than 180 Days to Make Home Lead-Safe: Wisconsin, 1996–1999

Factor	Crude OR (95% CI)	Adjusted OR (95% CI)
Gendera
Boy	1.40 (0.83, 2.35)	NA
Girl	Referent	Referent
Race
African American	2.95* (1.73, 5.01)	2.71* (1.56, 4.71)
White/Other	Referent	Referent
First BLL test, μg/dLa
35–40	0.55 (0.24, 1.26)	NA
30–34	1.11 (0.49, 2.49)	NA
25–29	0.98 (0.53, 1.84)	NA
20–24	Referent	NA
Age at first test, mo
≥ 25	2.24* (1.14, 4.42)	1.70 (0.82, 3.54)
13–24	2.07* (1.04, 4.10)	1.61 (0.78, 3.35)
0–12	Referent	Referent
Test year
1999	0.42* (0.20, 0.92)	0.41* (0.19, 0.92)
1998	0.50 (0.24, 1.06)	0.60 (0.27, 1.31)
1997	1.26 (0.64, 2.48)	1.28 (0.64, 2.57)
1996	Referent	Referent

Note. OR = odds ratio; CI = confidence interval; NA = not applicable; BLL = blood lead level. ^aNot used in multivariate analysis because not significant in univariate analysis.

*P < .05.

DISCUSSION

Because children spend more than 80% of their time indoors, their homes are important targets for preventing elevated BLLs.13 In our study population, only 18% of homes were deemed lead-safe within 6 months, whereas 45% required longer than 18 months to be deemed lead-safe. Because prolonged exposure adds potential health risks to children, it is unacceptable to keep children in homes that require long lengths of times for repair. Over the time period studied, the percentage of homes made lead-safe within 6 months improved from 16% to 31%, and the percentage of homes taking longer than 18 months decreased from 61% to 24%. We assumed, on the basis of our experiences in health departments, that the improvement in abatement times reflected the benefit of increased funding for efforts to reduce lead-based hazards in home settings. However, the resources available are still considerably lacking.

In 2001, the Wisconsin Department of Health and Family Services began requiring all local health departments that receive state funds for lead poisoning prevention to conduct investigations on the homes of children who have BLLs of 20 μg/dL or greater. This action has dramatically improved the number of homes investigated and the length of time to investigation. For example, in 2000, when investigations were not mandatory, only 42% of homes were investigated within 14 days of the health department’s receiving the BLL report; in 2004, more than 90% of these cases were investigated within 14 days.

Our study showed that African American children were twice as likely to live in homes that required more than 180 days to be deemed lead-safe. The majority of African American children in Wisconsin live in urban, lower-income communities. Although we did not ask about socioeconomic status, race may be an indicator for families with lower income, who tend to reside in rental housing units.5 Jacobs et al.5 reported that rental units had a higher prevalence of lead-based paint hazards than owner units and that among low-income households, 35% contained lead-based paint hazards, compared with 19% of upper-income families.3

Despite efforts for immediate inspection and strong remediation orders with short timelines, ensuring compliance remains problematic. Although rapid inspection and compliance orders will always be needed, primary prevention is the more efficient alternative. When sufficient housing is upgraded to “lead-safe” or “lead-free” and can be readily identified by renters with young children, we should begin to see fewer poisoned children.

One example of a regulation that may have a positive effect on reducing childhood lead poisoning is Wisconsin Act 113, enacted in 1999. Among other provisions, Act 113 mandates that a lead-free or lead-safe property registry be created.14 The registry encourages housing owners to bring their property into compliance with state standards, providing immunity from liability if a child is lead-poisoned while occupying a property with a lead-free/lead-safe certificate.

Community efforts targeted at educating families must be maintained. Families residing in homes with lead paint need to be aware of the hazards associated with ingestion of the paint, the common locations of the hazards (such as windows and cabinets), and proper cleaning techniques. Residents also should be provided contact information for state or local health departments or the US Department of Housing and Urban Development if landlords or property owners refuse to make needed repairs.

Although progress has been made in reducing the time needed to make homes lead-safe in Wisconsin, 24% of homes in 1999 still required longer than 6 months for such improvements. Stronger efforts should be made to reduce substantial delays in compliance with abatement orders.